<PAGE> PAGE 1
000 A000000 08/31/2000
000 C000000 0000780403
000 D000000 N
000 E000000 NF
000 F000000 Y
000 G000000 N
000 H000000 N
000 I000000 6.1
000 J000000 A
001 A000000 PAINEWEBBER MASTER SERIES, INC.
001 B000000 811-4448
001 C000000 2127133041
002 A000000 51 WEST 52ND STREET
002 B000000 NEW YORK
002 C000000 NY
002 D010000 10019
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 Y
007 B000000 2
007 C010100 1
007 C020100 PAINEWEBBER MONEY MARKET FUND
007 C030100 N
007 C010200 2
007 C010300 3
007 C010400 4
007 C010500 5
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
008 A00AA01 MITCHELL HUTCHINS ASSET MANAGEMENT INC.
008 B00AA01 A
008 C00AA01 801-13219
008 D01AA01 NEW YORK
008 D02AA01 NY
008 D03AA01 10019
010 A00AA01 MITCHELL HUTCHINS ASSET MANAGEMENT INC.
010 B00AA01 801-13219
010 C01AA01 NEW YORK
010 C02AA01 NY
010 C03AA01 10019
011 A00AA01 PAINEWEBBER INC.
011 B00AA01 8-16267
011 C01AA01 NEW YORK
011 C02AA01 NY
011 C03AA01 10019
012 A00AA01 PFPC, INC.
<PAGE> PAGE 2
012 B00AA01 84-0000000
012 C01AA01 WILMINGTON
012 C02AA01 DE
012 C03AA01 19809
013 A00AA01 PRICEWATERHOUSECOOPERS
013 B01AA01 NEW YORK
013 B02AA01 NY
013 B03AA01 10036
014 A00AA01 PAINEWEBBER INCORPORATED
014 B00AA01 8-16267
015 A00AA01 STATE STREET BANK AND TRUST COMPANY
015 B00AA01 C
015 C01AA01 NORTH QUINCY
015 C02AA01 MA
015 C03AA01 02171
015 E01AA01 X
018 00AA00 Y
019 A00AA00 Y
019 B00AA00 74
019 C00AA00 PAINEWEBBE
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 GOLDMAN SACHS
022 B000001 13-5108808
022 C000001 720764
022 D000001 0
022 A000002 MORGAN, J.P. SECURITIES
022 B000002 13-3224016
022 C000002 507902
022 D000002 0
022 A000003 MERRILL LYNCH PIERCE FENNER SMITH
022 B000003 13-5674085
022 C000003 300993
022 D000003 0
022 A000004 LEHMAN BROTHERS INC.
022 B000004 13-2518466
022 C000004 281073
022 D000004 0
022 A000005 HSBC
022 C000005 224852
022 D000005 0
022 A000006 MORGAN STANLEY AND CO., INC.
<PAGE> PAGE 3
022 B000006 13-2655998
022 C000006 150626
022 D000006 0
022 A000007 PRUDENTIAL SECURITIES INC.
022 B000007 22-2347336
022 C000007 87052
022 D000007 0
022 A000008 GENERAL MOTORS ACCEPTANCE CORP.
022 C000008 68929
022 D000008 0
022 A000009 HOUSEHOLD FINANCE
022 C000009 55456
022 D000009 0
022 A000010 CHASE BANK
022 C000010 31192
022 D000010 0
023 C000000 2550325
023 D000000 1928
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 N
026 B000000 N
026 C000000 N
026 D000000 Y
026 E000000 N
026 F000000 N
026 G010000 N
026 G020000 N
026 H000000 Y
027 000000 Y
028 A01AA00 36381
028 A02AA00 340
028 A03AA00 0
028 A04AA00 40542
028 B01AA00 32778
028 B02AA00 287
028 B03AA00 0
028 B04AA00 38104
028 C01AA00 33023
028 C02AA00 297
028 C03AA00 0
028 C04AA00 36076
028 D01AA00 46666
028 D02AA00 317
<PAGE> PAGE 4
028 D03AA00 0
028 D04AA00 56649
028 E01AA00 36424
028 E02AA00 245
028 E03AA00 0
028 E04AA00 38283
028 F01AA00 48636
028 F02AA00 269
028 F03AA00 0
028 F04AA00 49577
028 G01AA00 233908
028 G02AA00 1755
028 G03AA00 0
028 G04AA00 259231
028 H00AA00 0
029 00AA00 N
030 A00AA00 0
030 B00AA00 0.00
030 C00AA00 0.00
031 A00AA00 0
031 B00AA00 0
032 00AA00 0
033 00AA00 0
034 00AA00 Y
035 00AA00 173
036 A00AA00 N
036 B00AA00 0
037 00AA00 N
038 00AA00 0
039 00AA00 Y
040 00AA00 Y
041 00AA00 Y
042 A00AA00 0
042 B00AA00 0
042 C00AA00 0
042 D00AA00 0
042 E00AA00 0
042 F00AA00 0
042 G00AA00 0
042 H00AA00 100
043 00AA00 235
044 00AA00 0
045 00AA00 Y
046 00AA00 N
047 00AA00 Y
048 00AA00 0.500
048 A01AA00 0
048 A02AA00 0.000
048 B01AA00 0
048 B02AA00 0.000
048 C01AA00 0
<PAGE> PAGE 5
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 N
055 A00AA00 N
055 B00AA00 N
056 00AA00 Y
057 00AA00 N
058 A00AA00 N
059 00AA00 Y
060 A00AA00 Y
060 B00AA00 Y
061 00AA00 0
062 A00AA00 Y
062 B00AA00 0.0
062 C00AA00 28.3
062 D00AA00 0.0
062 E00AA00 0.0
<PAGE> PAGE 6
062 F00AA00 0.0
062 G00AA00 4.2
062 H00AA00 0.0
062 I00AA00 67.8
062 J00AA00 0.0
062 K00AA00 0.0
062 L00AA00 0.0
062 M00AA00 0.0
062 N00AA00 0.0
062 O00AA00 0.0
062 P00AA00 0.0
062 Q00AA00 0.0
062 R00AA00 0.0
063 A00AA00 22
063 B00AA00 0.0
064 A00AA00 N
064 B00AA00 N
066 A00AA00 N
067 00AA00 N
068 A00AA00 N
068 B00AA00 N
069 00AA00 N
070 A01AA00 Y
070 A02AA00 N
070 B01AA00 N
070 B02AA00 N
070 C01AA00 N
070 C02AA00 N
070 D01AA00 N
070 D02AA00 N
070 E01AA00 N
070 E02AA00 N
070 F01AA00 N
070 F02AA00 N
070 G01AA00 N
070 G02AA00 N
070 H01AA00 N
070 H02AA00 N
070 I01AA00 N
070 I02AA00 N
070 J01AA00 Y
070 J02AA00 N
070 K01AA00 Y
070 K02AA00 N
070 L01AA00 Y
070 L02AA00 Y
070 M01AA00 N
070 M02AA00 N
070 N01AA00 Y
070 N02AA00 N
070 O01AA00 Y
<PAGE> PAGE 7
070 O02AA00 N
070 P01AA00 Y
070 P02AA00 N
070 Q01AA00 N
070 Q02AA00 N
070 R01AA00 N
070 R02AA00 N
071 A00AA00 0
071 B00AA00 0
071 C00AA00 0
071 D00AA00 0
072 A00AA00 6
072 B00AA00 2542
072 C00AA00 0
072 D00AA00 0
072 E00AA00 0
072 F00AA00 199
072 G00AA00 0
072 H00AA00 0
072 I00AA00 26
072 J00AA00 5
072 K00AA00 8
072 L00AA00 17
072 M00AA00 5
072 N00AA00 20
072 O00AA00 0
072 P00AA00 0
072 Q00AA00 0
072 R00AA00 23
072 S00AA00 15
072 T00AA00 235
072 U00AA00 0
072 V00AA00 0
072 W00AA00 2
072 X00AA00 555
072 Y00AA00 0
072 Z00AA00 1987
072AA00AA00 0
072BB00AA00 0
072CC01AA00 0
072CC02AA00 0
072DD01AA00 686
072DD02AA00 1301
072EE00AA00 0
073 A01AA00 0.0270
073 A02AA00 0.0240
073 B00AA00 0.0000
073 C00AA00 0.0000
074 A00AA00 0
074 B00AA00 0
074 C00AA00 71321
<PAGE> PAGE 8
074 D00AA00 0
074 E00AA00 0
074 F00AA00 0
074 G00AA00 0
074 H00AA00 0
074 I00AA00 0
074 J00AA00 0
074 K00AA00 0
074 L00AA00 7846
074 M00AA00 32
074 N00AA00 79199
074 O00AA00 0
074 P00AA00 59
074 Q00AA00 0
074 R01AA00 0
074 R02AA00 0
074 R03AA00 0
074 R04AA00 8052
074 S00AA00 0
074 T00AA00 71088
074 U01AA00 31143
074 U02AA00 39946
074 V01AA00 1.00
074 V02AA00 1.00
074 W00AA00 0.9999
074 X00AA00 3074
074 Y00AA00 7508
075 A00AA00 79128
075 B00AA00 0
076 00AA00 0.00
077 A000000 Y
077 B000000 N
077 C000000 N
077 D000000 N
077 E000000 N
077 F000000 N
077 G000000 N
077 H000000 N
077 I000000 N
077 J000000 N
077 K000000 N
077 L000000 N
077 M000000 N
077 N000000 N
077 O000000 N
077 P000000 N
077 Q010000 Y
077 Q020000 N
077 Q030000 N
078 000000 N
080 C00AA00 0
<PAGE> PAGE 9
081 B00AA00 73
082 B00AA00 0
083 A00AA00 N
083 B00AA00 0
084 A00AA00 N
084 B00AA00 0
085 A00AA00 Y
085 B00AA00 N
086 A010000 0
086 A020000 0
086 B010000 0
086 B020000 0
086 C010000 0
086 C020000 0
086 D010000 0
086 D020000 0
086 E010000 0
086 E020000 0
086 F010000 0
086 F020000 0
SIGNATURE PAUL SCHUBERT
TITLE TREASURER
