<PAGE> PAGE 1
000 A000000 03/31/98
000 C000000 750756
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 3.0.a
000 J000000 A
001 A000000 SELIGMAN MUNICIPAL SERIES TRUST
001 B000000 811-4250
001 C000000 2128501864
002 A000000 100 PARK AVENUE
002 B000000 NEW YORK
002 C000000 NY
002 D010000 10017
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 Y
007 B000000 4
007 C010100 1
007 C020100 CALIFORNIA QUALITY SERIES
007 C030100 N
007 C010200 2
007 C020200 CALIFORNIA HIGH-YIELD SERIES
007 C030200 N
007 C010300 3
007 C010400 4
007 C020400 NORTH CAROLINA SERIES
007 C030400 N
007 C010500 5
007 C020500 FLORIDA SERIES
007 C030500 N
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
008 A00AA01 J. & W. SELIGMAN & CO., INCORPORATED
008 B00AA01 A
008 C00AA01 801-15798
008 D01AA01 NEW YORK
008 D02AA01 NY
008 D03AA01 10017
011 A00AA01 SELIGMAN FINANCIAL SERVICES INC.
011 B00AA01 8-25845
011 C01AA01 NEW YORK
011 C02AA01 NY
011 C03AA01 10017
<PAGE> PAGE 2
012 A00AA01 SELIGMAN DATA CORP.
012 B00AA01 85-1895
012 C01AA01 NEW YORK
012 C02AA01 NY
012 C03AA01 10017
013 A00AA01 DELOITTE & TOUCHE LLP
013 B01AA01 NEW YORK
013 B02AA01 NY
013 B03AA01 10281
014 A00AA01 SELIGMAN SERVICES, INC.
014 B00AA01 8-47717
015 A00AA01 INVESTORS FIDUCIARY TRUST COMPANY
015 B00AA01 C
015 C01AA01 KANSAS CITY
015 C02AA01 MO
015 C03AA01 64105
015 C04AA01 1716
015 E01AA01 X
018 00AA00 Y
019 A00AA00 Y
019 B00AA00 50
019 C00AA00 JWSELIGMAN
020 C000001 0
020 C000002 0
020 C000003 0
020 C000004 0
020 C000005 0
020 C000006 0
020 C000007 0
020 C000008 0
020 C000009 0
020 C000010 0
021 000000 0
022 A000001 LEHMAN BROTHERS, INC.
022 B000001 13-2518466
022 C000001 23743
022 D000001 27500
022 A000002 SMITH BARNEY INC.
022 B000002 13-1912900
022 C000002 9761
022 D000002 7715
022 A000003 GOLDMAN SACHS & CO.
022 B000003 13-5108880
022 C000003 7593
022 D000003 9333
022 A000004 A.F. BEST SECURITIES INC.
022 B000004 59-2325576
022 C000004 7926
022 D000004 5185
022 A000005 FIRST CHICAGO CAPITAL MARKETS
022 B000005 36-3595942
<PAGE> PAGE 3
022 C000005 2500
022 D000005 2500
022 A000006 BEAR STEARNS & CO., INC.
022 B000006 13-3299429
022 C000006 1000
022 D000006 3556
022 A000007 MERRILL LYNCH, PIERCE, FENNER & SMITH INC.
022 B000007 13-5674085
022 C000007 0
022 D000007 3998
022 A000008 BANC AMERICA SECURITIES, INC.
022 B000008 95-4035346
022 C000008 3976
022 D000008 0
022 A000009 INTERSTATE/JOHNSON LANE
022 B000009 56-0276690
022 C000009 1480
022 D000009 1546
022 A000010 H. J. MEYERS & CO., INC.
022 B000010 16-1228688
022 C000010 2838
022 D000010 0
023 C000000 67416
023 D000000 65225
024 00AA00 N
025 D00AA01 0
025 D00AA02 0
025 D00AA03 0
025 D00AA04 0
025 D00AA05 0
025 D00AA06 0
025 D00AA07 0
025 D00AA08 0
026 A000000 Y
026 B000000 Y
026 C000000 Y
026 D000000 Y
026 E000000 N
026 F000000 Y
026 G010000 N
026 G020000 N
026 H000000 Y
027 000000 Y
037 00AA00 N
038 00AA00 0
039 00AA00 N
040 00AA00 Y
041 00AA00 Y
045 00AA00 Y
046 00AA00 N
047 00AA00 Y
<PAGE> PAGE 4
048 00AA00 0.500
048 A01AA00 0
048 A02AA00 0.000
048 B01AA00 0
048 B02AA00 0.000
048 C01AA00 0
048 C02AA00 0.000
048 D01AA00 0
048 D02AA00 0.000
048 E01AA00 0
048 E02AA00 0.000
048 F01AA00 0
048 F02AA00 0.000
048 G01AA00 0
048 G02AA00 0.000
048 H01AA00 0
048 H02AA00 0.000
048 I01AA00 0
048 I02AA00 0.000
048 J01AA00 0
048 J02AA00 0.000
048 K01AA00 0
048 K02AA00 0.000
049 00AA00 N
050 00AA00 N
051 00AA00 N
052 00AA00 N
053 A00AA00 N
054 A00AA00 Y
054 B00AA00 Y
054 C00AA00 N
054 D00AA00 N
054 E00AA00 N
054 F00AA00 N
054 G00AA00 Y
054 H00AA00 Y
054 I00AA00 N
054 J00AA00 Y
054 K00AA00 N
054 L00AA00 N
054 M00AA00 Y
054 N00AA00 N
054 O00AA00 Y
058 A00AA00 N
059 00AA00 Y
060 A00AA00 N
060 B00AA00 N
061 00AA00 1000
066 A00AA00 N
067 00AA00 N
068 A00AA00 N
<PAGE> PAGE 5
068 B00AA00 N
069 00AA00 N
077 A000000 N
078 000000 N
080 C00AA00 0
081 B00AA00 0
082 B00AA00 0
083 B00AA00 0
084 B00AA00 0
028 A010100 5138
028 A020100 190
028 A030100 0
028 A040100 4461
028 B010100 497
028 B020100 428
028 B030100 0
028 B040100 1044
028 C010100 1863
028 C020100 175
028 C030100 0
028 C040100 2521
028 D010100 2138
028 D020100 194
028 D030100 0
028 D040100 2435
028 E010100 396
028 E020100 173
028 E030100 0
028 E040100 1512
028 F010100 958
028 F020100 166
028 F030100 0
028 F040100 1803
028 G010100 10990
028 G020100 1326
028 G030100 0
028 G040100 13776
028 H000100 1397
029 000100 Y
030 A000100 52
030 B000100 4.75
030 C000100 0.00
031 A000100 6
031 B000100 0
032 000100 45
033 000100 1
034 000100 Y
035 000100 0
036 A000100 N
036 B000100 0
042 A000100 0
<PAGE> PAGE 6
042 B000100 0
042 C000100 0
042 D000100 100
042 E000100 0
042 F000100 0
042 G000100 0
042 H000100 0
043 000100 48
044 000100 0
055 A000100 N
055 B000100 N
056 000100 Y
057 000100 N
062 A000100 Y
062 B000100 0.0
062 C000100 0.0
062 D000100 0.0
062 E000100 0.8
062 F000100 0.0
062 G000100 0.0
062 H000100 0.0
062 I000100 0.0
062 J000100 0.0
062 K000100 0.0
062 L000100 1.3
062 M000100 97.9
062 N000100 0.0
062 O000100 0.0
062 P000100 0.0
062 Q000100 0.0
062 R000100 0.0
063 A000100 0
063 B000100 21.6
064 A000100 Y
064 B000100 N
070 A010100 Y
070 A020100 N
070 B010100 N
070 B020100 N
070 C010100 N
070 C020100 N
070 D010100 N
070 D020100 N
070 E010100 N
070 E020100 N
070 F010100 N
070 F020100 N
070 G010100 N
070 G020100 N
070 H010100 N
070 H020100 N
<PAGE> PAGE 7
070 I010100 N
070 I020100 N
070 J010100 Y
070 J020100 N
070 K010100 N
070 K020100 N
070 L010100 N
070 L020100 N
070 M010100 N
070 M020100 N
070 N010100 N
070 N020100 N
070 O010100 N
070 O020100 N
070 P010100 Y
070 P020100 N
070 Q010100 N
070 Q020100 N
070 R010100 N
070 R020100 N
071 A000100 17965
071 B000100 20271
071 C000100 87077
071 D000100 21
072 A000100 6
072 B000100 2488
072 C000100 0
072 D000100 0
072 E000100 0
072 F000100 223
072 G000100 0
072 H000100 0
072 I000100 49
072 J000100 4
072 K000100 3
072 L000100 6
072 M000100 4
072 N000100 3
072 O000100 1
072 P000100 0
072 Q000100 0
072 R000100 8
072 S000100 3
072 T000100 48
072 U000100 0
072 V000100 0
072 W000100 1
072 X000100 353
072 Y000100 0
072 Z000100 2135
072AA000100 2135
<PAGE> PAGE 8
072BB000100 0
072CC010100 0
072CC020100 1266
072DD010100 2097
072DD020100 38
072EE000100 420
073 A010100 0.1679
073 A020100 0.1361
073 B000100 0.0330
073 C000100 0.0000
074 A000100 189
074 B000100 0
074 C000100 700
074 D000100 85779
074 E000100 0
074 F000100 0
074 G000100 0
074 H000100 0
074 I000100 0
074 J000100 0
074 K000100 10
074 L000100 1285
074 M000100 4
074 N000100 87967
074 O000100 0
074 P000100 37
074 Q000100 0
074 R010100 0
074 R020100 0
074 R030100 0
074 R040100 273
074 S000100 0
074 T000100 87657
074 U010100 12222
074 U020100 254
074 V010100 7.03
074 V020100 7.01
074 W000100 0.0000
074 X000100 1509
074 Y000100 0
075 A000100 0
075 B000100 89144
076 000100 0.00
028 A010200 1078
028 A020200 128
028 A030200 0
028 A040200 931
028 B010200 1147
028 B020200 305
028 B030200 0
028 B040200 695
<PAGE> PAGE 9
028 C010200 2243
028 C020200 120
028 C030200 0
028 C040200 412
028 D010200 2642
028 D020200 142
028 D030200 0
028 D040200 1488
028 E010200 912
028 E020200 126
028 E030200 0
028 E040200 459
028 F010200 1244
028 F020200 124
028 F030200 0
028 F040200 1567
028 G010200 9266
028 G020200 945
028 G030200 0
028 G040200 5552
028 H000200 1989
029 000200 Y
030 A000200 69
030 B000200 4.75
030 C000200 0.00
031 A000200 9
031 B000200 0
032 000200 60
033 000200 0
034 000200 Y
035 000200 2
036 A000200 N
036 B000200 0
042 A000200 0
042 B000200 0
042 C000200 0
042 D000200 100
042 E000200 0
042 F000200 0
042 G000200 0
042 H000200 0
043 000200 45
044 000200 0
055 A000200 N
055 B000200 N
056 000200 Y
057 000200 N
062 A000200 Y
062 B000200 0.0
062 C000200 0.0
062 D000200 0.0
<PAGE> PAGE 10
062 E000200 0.3
062 F000200 0.0
062 G000200 0.0
062 H000200 0.0
062 I000200 0.0
062 J000200 0.0
062 K000200 0.0
062 L000200 1.2
062 M000200 0.0
062 N000200 0.0
062 O000200 98.5
062 P000200 0.0
062 Q000200 0.0
062 R000200 0.0
063 A000200 0
063 B000200 22.5
064 A000200 Y
064 B000200 N
070 A010200 Y
070 A020200 N
070 B010200 N
070 B020200 N
070 C010200 N
070 C020200 N
070 D010200 N
070 D020200 N
070 E010200 N
070 E020200 N
070 F010200 N
070 F020200 N
070 G010200 N
070 G020200 N
070 H010200 N
070 H020200 N
070 I010200 N
070 I020200 N
070 J010200 Y
070 J020200 N
070 K010200 N
070 K020200 N
070 L010200 N
070 L020200 N
070 M010200 N
070 M020200 N
070 N010200 N
070 N020200 N
070 O010200 N
070 O020200 N
070 P010200 Y
070 P020200 Y
070 Q010200 N
<PAGE> PAGE 11
070 Q020200 N
070 R010200 N
070 R020200 N
071 A000200 11352
071 B000200 4803
071 C000200 55881
071 D000200 9
072 A000200 6
072 B000200 1661
072 C000200 0
072 D000200 0
072 E000200 0
072 F000200 147
072 G000200 0
072 H000200 0
072 I000200 35
072 J000200 4
072 K000200 3
072 L000200 7
072 M000200 4
072 N000200 1
072 O000200 1
072 P000200 0
072 Q000200 0
072 R000200 8
072 S000200 4
072 T000200 45
072 U000200 0
072 V000200 0
072 W000200 1
072 X000200 260
072 Y000200 0
072 Z000200 1401
072AA000200 183
072BB000200 0
072CC010200 554
072CC020200 0
072DD010200 1320
072DD020200 81
072EE000200 272
073 A010200 0.1590
073 A020200 0.1290
073 B000200 0.0320
073 C000200 0.0000
074 A000200 128
074 B000200 0
074 C000200 200
074 D000200 60406
074 E000200 0
074 F000200 0
074 G000200 0
<PAGE> PAGE 12
074 H000200 0
074 I000200 0
074 J000200 0
074 K000200 7
074 L000200 1080
074 M000200 6
074 N000200 61827
074 O000200 0
074 P000200 33
074 Q000200 0
074 R010200 0
074 R020200 0
074 R030200 0
074 R040200 468
074 S000200 0
074 T000200 61326
074 U010200 8393
074 U020200 814
074 V010200 6.66
074 V020200 6.67
074 W000200 0.0000
074 X000200 1089
074 Y000200 0
075 A000200 0
075 B000200 59132
076 000200 0.00
028 A010400 94
028 A020400 68
028 A030400 0
028 A040400 208
028 B010400 202
028 B020400 263
028 B030400 0
028 B040400 559
028 C010400 74
028 C020400 64
028 C030400 0
028 C040400 254
028 D010400 166
028 D020400 71
028 D030400 0
028 D040400 487
028 E010400 234
028 E020400 64
028 E030400 0
028 E040400 251
028 F010400 288
028 F020400 63
028 F030400 0
028 F040400 170
028 G010400 1058
<PAGE> PAGE 13
028 G020400 593
028 G030400 0
028 G040400 1929
028 H000400 864
029 000400 Y
030 A000400 32
030 B000400 4.75
030 C000400 0.00
031 A000400 4
031 B000400 0
032 000400 28
033 000400 0
034 000400 Y
035 000400 0
036 A000400 N
036 B000400 0
042 A000400 0
042 B000400 0
042 C000400 0
042 D000400 100
042 E000400 0
042 F000400 0
042 G000400 0
042 H000400 0
043 000400 43
044 000400 0
055 A000400 Y
055 B000400 N
056 000400 Y
057 000400 N
062 A000400 Y
062 B000400 0.0
062 C000400 0.0
062 D000400 0.0
062 E000400 0.0
062 F000400 0.0
062 G000400 0.0
062 H000400 0.0
062 I000400 0.0
062 J000400 0.0
062 K000400 0.0
062 L000400 1.6
062 M000400 98.4
062 N000400 0.0
062 O000400 0.0
062 P000400 0.0
062 Q000400 0.0
062 R000400 0.0
063 A000400 0
063 B000400 22.4
064 A000400 Y
<PAGE> PAGE 14
064 B000400 N
070 A010400 Y
070 A020400 N
070 B010400 N
070 B020400 N
070 C010400 N
070 C020400 N
070 D010400 N
070 D020400 N
070 E010400 N
070 E020400 N
070 F010400 N
070 F020400 N
070 G010400 N
070 G020400 N
070 H010400 N
070 H020400 N
070 I010400 N
070 I020400 N
070 J010400 Y
070 J020400 N
070 K010400 N
070 K020400 N
070 L010400 N
070 L020400 N
070 M010400 N
070 M020400 N
070 N010400 N
070 N020400 N
070 O010400 N
070 O020400 N
070 P010400 Y
070 P020400 N
070 Q010400 N
070 Q020400 N
070 R010400 N
070 R020400 N
071 A000400 4398
071 B000400 4558
071 C000400 33632
071 D000400 13
072 A000400 6
072 B000400 931
072 C000400 0
072 D000400 0
072 E000400 0
072 F000400 84
072 G000400 0
072 H000400 0
072 I000400 23
072 J000400 6
<PAGE> PAGE 15
072 K000400 2
072 L000400 6
072 M000400 3
072 N000400 2
072 O000400 0
072 P000400 0
072 Q000400 0
072 R000400 8
072 S000400 4
072 T000400 43
072 U000400 0
072 V000400 0
072 W000400 1
072 X000400 182
072 Y000400 0
072 Z000400 749
072AA000400 312
072BB000400 0
072CC010400 184
072CC020400 0
072DD010400 726
072DD020400 23
072EE000400 269
073 A010400 0.1788
073 A020400 0.1479
073 B000400 0.0640
073 C000400 0.0000
074 A000400 136
074 B000400 0
074 C000400 0
074 D000400 33305
074 E000400 0
074 F000400 0
074 G000400 0
074 H000400 0
074 I000400 0
074 J000400 0
074 K000400 5
074 L000400 531
074 M000400 4
074 N000400 33981
074 O000400 0
074 P000400 14
074 Q000400 0
074 R010400 0
074 R020400 0
074 R030400 0
074 R040400 116
074 S000400 0
074 T000400 33851
074 U010400 4019
<PAGE> PAGE 16
074 U020400 158
074 V010400 8.10
074 V020400 8.10
074 W000400 0.0000
074 X000400 857
074 Y000400 0
075 A000400 0
075 B000400 33842
076 000400 0.00
028 A010500 99
028 A020500 68
028 A030500 0
028 A040500 504
028 B010500 524
028 B020500 300
028 B030500 0
028 B040500 272
028 C010500 951
028 C020500 66
028 C030500 0
028 C040500 334
028 D010500 252
028 D020500 73
028 D030500 0
028 D040500 485
028 E010500 176
028 E020500 64
028 E030500 0
028 E040500 1011
028 F010500 997
028 F020500 60
028 F030500 0
028 F040500 909
028 G010500 2999
028 G020500 631
028 G030500 0
028 G040500 3515
028 H000500 936
029 000500 Y
030 A000500 40
030 B000500 4.75
030 C000500 0.00
031 A000500 5
031 B000500 0
032 000500 35
033 000500 0
034 000500 Y
035 000500 0
036 A000500 N
036 B000500 0
042 A000500 0
<PAGE> PAGE 17
042 B000500 0
042 C000500 0
042 D000500 100
042 E000500 0
042 F000500 0
042 G000500 0
042 H000500 0
043 000500 62
044 000500 0
055 A000500 Y
055 B000500 N
056 000500 Y
057 000500 N
062 A000500 Y
062 B000500 0.0
062 C000500 0.0
062 D000500 0.0
062 E000500 0.7
062 F000500 0.0
062 G000500 0.0
062 H000500 0.0
062 I000500 0.0
062 J000500 0.0
062 K000500 0.0
062 L000500 1.6
062 M000500 97.7
062 N000500 0.0
062 O000500 0.0
062 P000500 0.0
062 Q000500 0.0
062 R000500 0.0
063 A000500 0
063 B000500 24.1
064 A000500 Y
064 B000500 N
070 A010500 Y
070 A020500 N
070 B010500 N
070 B020500 N
070 C010500 N
070 C020500 N
070 D010500 N
070 D020500 N
070 E010500 N
070 E020500 N
070 F010500 N
070 F020500 N
070 G010500 N
070 G020500 N
070 H010500 N
070 H020500 N
<PAGE> PAGE 18
070 I010500 N
070 I020500 N
070 J010500 Y
070 J020500 N
070 K010500 N
070 K020500 N
070 L010500 N
070 L020500 N
070 M010500 N
070 M020500 N
070 N010500 N
070 N020500 N
070 O010500 N
070 O020500 N
070 P010500 Y
070 P020500 N
070 Q010500 N
070 Q020500 N
070 R010500 N
070 R020500 N
071 A000500 1950
071 B000500 2621
071 C000500 43481
071 D000500 4
072 A000500 6
072 B000500 1217
072 C000500 0
072 D000500 0
072 E000500 0
072 F000500 111
072 G000500 0
072 H000500 0
072 I000500 27
072 J000500 4
072 K000500 2
072 L000500 5
072 M000500 3
072 N000500 2
072 O000500 0
072 P000500 0
072 Q000500 0
072 R000500 8
072 S000500 4
072 T000500 62
072 U000500 0
072 V000500 0
072 W000500 2
072 X000500 230
072 Y000500 0
072 Z000500 987
072AA000500 186
<PAGE> PAGE 19
072BB000500 0
072CC010500 671
072CC020500 0
072DD010500 954
072DD020500 33
072EE000500 401
073 A010500 0.1748
073 A020500 0.1457
073 B000500 0.0720
073 C000500 0.0000
074 A000500 149
074 B000500 0
074 C000500 300
074 D000500 43260
074 E000500 0
074 F000500 0
074 G000500 0
074 H000500 0
074 I000500 0
074 J000500 0
074 K000500 5
074 L000500 935
074 M000500 4
074 N000500 44653
074 O000500 0
074 P000500 18
074 Q000500 0
074 R010500 0
074 R020500 0
074 R030500 0
074 R040500 362
074 S000500 0
074 T000500 44273
074 U010500 5371
074 U020500 250
074 V010500 7.88
074 V020500 7.89
074 W000500 0.0000
074 X000500 778
074 Y000500 0
075 A000500 0
075 B000500 44254
076 000500 0.00
SIGNATURE THOMAS G. ROSE
TITLE TREASURER
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>021
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-CALIFORNA HIGH-YIELD CL A
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 57005
<INVESTMENTS-AT-VALUE> 60606
<RECEIVABLES> 1093
<ASSETS-OTHER> 128
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 61827
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 501
<TOTAL-LIABILITIES> 501
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 57696
<SHARES-COMMON-STOCK> 8393<F1>
<SHARES-COMMON-PRIOR> 8005<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 29
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 3601
<NET-ASSETS> 55896<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 1544<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (224)<F1>
<NET-INVESTMENT-INCOME> 1320<F1>
<REALIZED-GAINS-CURRENT> 183
<APPREC-INCREASE-CURRENT> 554
<NET-CHANGE-FROM-OPS> 2138
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (1320)<F1>
<DISTRIBUTIONS-OF-GAINS> (255)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 995<F1>
<NUMBER-OF-SHARES-REDEEMED> (739)<F1>
<SHARES-REINVESTED> 132<F1>
<NET-CHANGE-IN-ASSETS> 5123
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 118
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 137<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 224<F1>
<AVERAGE-NET-ASSETS> 54841<F1>
<PER-SHARE-NAV-BEGIN> 6.61<F1>
<PER-SHARE-NII> .16<F1>
<PER-SHARE-GAIN-APPREC> .08<F1>
<PER-SHARE-DIVIDEND> (.16)<F1>
<PER-SHARE-DISTRIBUTIONS> (.03)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 6.66<F1>
<EXPENSE-RATIO> .82<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class A only. All other data are fund level.
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>024
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-CALIFORNA HIGH-YIELD CL D
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 57005
<INVESTMENTS-AT-VALUE> 60606
<RECEIVABLES> 1093
<ASSETS-OTHER> 128
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 61827
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 501
<TOTAL-LIABILITIES> 501
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 57696
<SHARES-COMMON-STOCK> 814<F1>
<SHARES-COMMON-PRIOR> 502<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 29
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 3601
<NET-ASSETS> 5430<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 117<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (36)<F1>
<NET-INVESTMENT-INCOME> 81<F1>
<REALIZED-GAINS-CURRENT> 183
<APPREC-INCREASE-CURRENT> 554
<NET-CHANGE-FROM-OPS> 2138
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (81)<F1>
<DISTRIBUTIONS-OF-GAINS> (17)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 398<F1>
<NUMBER-OF-SHARES-REDEEMED> (96)<F1>
<SHARES-REINVESTED> 10<F1>
<NET-CHANGE-IN-ASSETS> 5123
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 118
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 10<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 36<F1>
<AVERAGE-NET-ASSETS> 4171<F1>
<PER-SHARE-NAV-BEGIN> 6.61<F1>
<PER-SHARE-NII> .13<F1>
<PER-SHARE-GAIN-APPREC> .09<F1>
<PER-SHARE-DIVIDEND> (.13)<F1>
<PER-SHARE-DISTRIBUTIONS> (.03)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 6.67<F1>
<EXPENSE-RATIO> 1.73<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class D only. All other data are fund level.
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>011
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-CALIFORNA QUALITY CL A
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 81594
<INVESTMENTS-AT-VALUE> 86479
<RECEIVABLES> 1299
<ASSETS-OTHER> 189
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 87967
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 310
<TOTAL-LIABILITIES> 310
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 80860
<SHARES-COMMON-STOCK> 12222<F1>
<SHARES-COMMON-PRIOR> 12445<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 1912
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 4885
<NET-ASSETS> 85876<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 2434<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (337)<F1>
<NET-INVESTMENT-INCOME> 2097<F1>
<REALIZED-GAINS-CURRENT> 2135
<APPREC-INCREASE-CURRENT> (1266)
<NET-CHANGE-FROM-OPS> 3004
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (2097)<F1>
<DISTRIBUTIONS-OF-GAINS> (411)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 1281<F1>
<NUMBER-OF-SHARES-REDEEMED> (1689)<F1>
<SHARES-REINVESTED> 185<F1>
<NET-CHANGE-IN-ASSETS> (1012)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 197
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 218<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 337<F1>
<AVERAGE-NET-ASSETS> 87375<F1>
<PER-SHARE-NAV-BEGIN> 6.99<F1>
<PER-SHARE-NII> .17<F1>
<PER-SHARE-GAIN-APPREC> .07<F1>
<PER-SHARE-DIVIDEND> (.17)<F1>
<PER-SHARE-DISTRIBUTIONS> (.03)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 7.03<F1>
<EXPENSE-RATIO> .77<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class A only. All other data are fund level.
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>014
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-CALIFORNA QUALITY CL D
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 81594
<INVESTMENTS-AT-VALUE> 86479
<RECEIVABLES> 1299
<ASSETS-OTHER> 189
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 87967
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 310
<TOTAL-LIABILITIES> 310
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 80860
<SHARES-COMMON-STOCK> 254<F1>
<SHARES-COMMON-PRIOR> 240<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 1912
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 4885
<NET-ASSETS> 1781<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 54<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (16)<F1>
<NET-INVESTMENT-INCOME> 38<F1>
<REALIZED-GAINS-CURRENT> 2135
<APPREC-INCREASE-CURRENT> (1266)
<NET-CHANGE-FROM-OPS> 3004
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (38)<F1>
<DISTRIBUTIONS-OF-GAINS> (9)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 284<F1>
<NUMBER-OF-SHARES-REDEEMED> (274)<F1>
<SHARES-REINVESTED> 4<F1>
<NET-CHANGE-IN-ASSETS> (1012)
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 197
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 16<F1>
<AVERAGE-NET-ASSETS> 1940<F1>
<PER-SHARE-NAV-BEGIN> 6.97<F1>
<PER-SHARE-NII> .14<F1>
<PER-SHARE-GAIN-APPREC> .07<F1>
<PER-SHARE-DIVIDEND> (.14)<F1>
<PER-SHARE-DISTRIBUTIONS> (.03)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 7.01<F1>
<EXPENSE-RATIO> 1.68<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class D only. All other data are fund level.
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>051
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-FLORIDA CL A
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 41303
<INVESTMENTS-AT-VALUE> 43560
<RECEIVABLES> 944
<ASSETS-OTHER> 149
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 44653
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 380
<TOTAL-LIABILITIES> 380
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 41831
<SHARES-COMMON-STOCK> 5371<F1>
<SHARES-COMMON-PRIOR> 5390<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 185
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 2257
<NET-ASSETS> 42301<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 1169<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (215)<F1>
<NET-INVESTMENT-INCOME> 954<F1>
<REALIZED-GAINS-CURRENT> 186
<APPREC-INCREASE-CURRENT> 671
<NET-CHANGE-FROM-OPS> 1844
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (954)<F1>
<DISTRIBUTIONS-OF-GAINS> (385)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 315<F1>
<NUMBER-OF-SHARES-REDEEMED> (410)<F1>
<SHARES-REINVESTED> 76<F1>
<NET-CHANGE-IN-ASSETS> 571
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 400
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 106<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 215<F1>
<AVERAGE-NET-ASSETS> 42616<F1>
<PER-SHARE-NAV-BEGIN> 7.80<F1>
<PER-SHARE-NII> .18<F1>
<PER-SHARE-GAIN-APPREC> .15<F1>
<PER-SHARE-DIVIDEND> (.18)<F1>
<PER-SHARE-DISTRIBUTIONS> (.07)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 7.88<F1>
<EXPENSE-RATIO> 1.00<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class A only. All other data are fund level.
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>054
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-FLORIDA CL D
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 41303
<INVESTMENTS-AT-VALUE> 43560
<RECEIVABLES> 944
<ASSETS-OTHER> 149
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 44653
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 380
<TOTAL-LIABILITIES> 380
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 41831
<SHARES-COMMON-STOCK> 250<F1>
<SHARES-COMMON-PRIOR> 215<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 185
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 2257
<NET-ASSETS> 1972<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 48<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (15)<F1>
<NET-INVESTMENT-INCOME> 33<F1>
<REALIZED-GAINS-CURRENT> 186
<APPREC-INCREASE-CURRENT> 671
<NET-CHANGE-FROM-OPS> 1844
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (33)<F1>
<DISTRIBUTIONS-OF-GAINS> (16)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 66<F1>
<NUMBER-OF-SHARES-REDEEMED> (35)<F1>
<SHARES-REINVESTED> 4<F1>
<NET-CHANGE-IN-ASSETS> 571
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 400
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 5<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 15<F1>
<AVERAGE-NET-ASSETS> 1753<F1>
<PER-SHARE-NAV-BEGIN> 7.81<F1>
<PER-SHARE-NII> .15<F1>
<PER-SHARE-GAIN-APPREC> .15<F1>
<PER-SHARE-DIVIDEND> (.15)<F1>
<PER-SHARE-DISTRIBUTIONS> (.07)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 7.89<F1>
<EXPENSE-RATIO> 1.76<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class D only. All other data are fund level.
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>041
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-NORTH CAROLINA CL A
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 31499
<INVESTMENTS-AT-VALUE> 33305
<RECEIVABLES> 540
<ASSETS-OTHER> 136
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 33981
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 130
<TOTAL-LIABILITIES> 130
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 31739
<SHARES-COMMON-STOCK> 4019<F1>
<SHARES-COMMON-PRIOR> 4061<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 306
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1806
<NET-ASSETS> 32569<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 897<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (171)<F1>
<NET-INVESTMENT-INCOME> 726<F1>
<REALIZED-GAINS-CURRENT> 312
<APPREC-INCREASE-CURRENT> 184
<NET-CHANGE-FROM-OPS> 1246
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (726)<F1>
<DISTRIBUTIONS-OF-GAINS> (259)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 121<F1>
<NUMBER-OF-SHARES-REDEEMED> (233)<F1>
<SHARES-REINVESTED> 70<F1>
<NET-CHANGE-IN-ASSETS> 50
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 263
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 81<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 171<F1>
<AVERAGE-NET-ASSETS> 32613<F1>
<PER-SHARE-NAV-BEGIN> 8.05<F1>
<PER-SHARE-NII> .18<F1>
<PER-SHARE-GAIN-APPREC> .11<F1>
<PER-SHARE-DIVIDEND> (.18)<F1>
<PER-SHARE-DISTRIBUTIONS> (.06)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 8.10<F1>
<EXPENSE-RATIO> 1.05<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class A only. All other data are fund level.
</FN>
</TABLE>
<TABLE> <S> <C>
<ARTICLE> 6
<SERIES>
<NUMBER>044
<NAME> SELIGMAN MUNICIPAL SERIES TRUST-NORTH CAROLINA CL D
<MULTIPLIER> 1000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> MAR-31-1998
<PERIOD-END> MAR-31-1998
<INVESTMENTS-AT-COST> 31499
<INVESTMENTS-AT-VALUE> 33305
<RECEIVABLES> 540
<ASSETS-OTHER> 136
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 33981
<PAYABLE-FOR-SECURITIES> 0
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 130
<TOTAL-LIABILITIES> 130
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 31739
<SHARES-COMMON-STOCK> 158<F1>
<SHARES-COMMON-PRIOR> 151<F1>
<ACCUMULATED-NII-CURRENT> 0
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 306
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 1806
<NET-ASSETS> 1282<F1>
<DIVIDEND-INCOME> 0
<INTEREST-INCOME> 34<F1>
<OTHER-INCOME> 0
<EXPENSES-NET> (11)<F1>
<NET-INVESTMENT-INCOME> 23<F1>
<REALIZED-GAINS-CURRENT> 312
<APPREC-INCREASE-CURRENT> 184
<NET-CHANGE-FROM-OPS> 1246
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> (23)<F1>
<DISTRIBUTIONS-OF-GAINS> (10)<F1>
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 9<F1>
<NUMBER-OF-SHARES-REDEEMED> (5)<F1>
<SHARES-REINVESTED> 3<F1>
<NET-CHANGE-IN-ASSETS> 50
<ACCUMULATED-NII-PRIOR> 0
<ACCUMULATED-GAINS-PRIOR> 263
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3<F1>
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 11<F1>
<AVERAGE-NET-ASSETS> 1226<F1>
<PER-SHARE-NAV-BEGIN> 8.05<F1>
<PER-SHARE-NII> .15<F1>
<PER-SHARE-GAIN-APPREC> .11<F1>
<PER-SHARE-DIVIDEND> (.15)<F1>
<PER-SHARE-DISTRIBUTIONS> (.06)<F1>
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 8.10<F1>
<EXPENSE-RATIO> 1.82<F1>
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
<FN>
<F1>Class D only. All other data are fund level.
</FN>
</TABLE>
