<PAGE> PAGE 1
000 B000000 09/30/96
000 C000000 0000711674
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 DEAN WITTER DEVELOPING GROWTH SECURITIES TRUS
001 B000000 811-3639
001 C000000 2123922550
002 A000000 TWO WORLD TRADE CENTER
002 B000000 NEW YORK
002 C000000 NY
002 D010000 10048
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 N
007 B000000 0
007 C010100 1
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 A000001 DEAN WITTER INTERCAPITAL INC.
008 B000001 A
008 C000001 801-42061
008 D010001 NEW YORK
008 D020001 NY
008 D030001 10048
010 A000001 DELETE
011 A000001 DEAN WITTER DISTRIBUTORS INC.
011 B000001 8-45262
011 C010001 NEW YORK
011 C020001 NY
011 C030001 10048
012 A000001 DEAN WITTER TRUST COMPANY
012 B000001 84-1785
012 C010001 JERSEY CITY
012 C020001 NJ
012 C030001 07302
013 A000001 PRICE WATERHOUSE LLP
013 B010001 NEW YORK
<PAGE> PAGE 2
013 B020001 NY
013 B030001 10036
014 A000001 DEAN WITTER REYNOLDS INC.
014 B000001 8-14172
015 A000001 THE BANK OF NEW YORK
015 B000001 C
015 C010001 NEW YORK
015 C020001 NY
015 C030001 10286
015 E010001 X
018 000000 Y
019 A000000 Y
019 B000000 122
019 C000000 DEANWITTER
020 A000001 DEAN WITTER REYNOLDS,INC
020 B000001 94-1671384
020 C000001 134
020 A000002 INSTINET CORPORATION
020 B000002 13-3443395
020 C000002 132
020 A000003 MONTGOMERY SECURITIES
020 B000003 94-1701676
020 C000003 73
020 A000004 MORGAN STANLEY & COMPANY INC.
020 B000004 13-2655998
020 C000004 70
020 A000005 WEEDAN & CO. L.P.
020 B000005 13-3364318
020 C000005 54
020 A000006 CHICAGO CORP.
020 B000006 36-2549961
020 C000006 50
020 A000007 MERRILL LYNCH, PIERCE, FENNER & SMITH INC.
020 B000007 13-5674085
020 C000007 48
020 A000008 BEAR STEARNS & CO. INC.
020 B000008 13-3299429
020 C000008 46
020 A000009 NATWEST SECURITIES CORP.
020 B000009 13-3312778
020 C000009 41
020 A000010 SMITH BARNEY SHEARSON INC.
020 B000010 13-1912900
020 C000010 39
021 000000 1361
022 A000001 BA SECURITIES, INC.
022 B000001 95-4035346
022 C000001 3363971
022 D000001 0
022 A000002 GOLDMAN SACHS & CO.
022 B000002 13-5108880
<PAGE> PAGE 3
022 C000002 877982
022 D000002 39735
022 A000003 THE BANK OF NEW YORK
022 B000003 13-5160382
022 C000003 480141
022 D000003 0
022 A000004 FORD MOTOR CREDIT CO.
022 B000004 38-1612444
022 C000004 416629
022 D000004 4999
022 A000005 GENERAL ELECTRIC CAPITAL CORP.
022 B000005 13-1500700
022 C000005 275700
022 D000005 9998
022 A000006 MORGAN STANLEY & CO. INC.
022 B000006 13-2655998
022 C000006 158522
022 D000006 40206
022 A000007 C S FIRST BOSTON CORP.
022 B000007 13-5674085
022 C000007 180620
022 D000007 17677
022 A000008 MERRILL LYNCH PIERCE FENNER & SMITH
022 B000008 13-5108880
022 C000008 111698
022 D000008 56885
022 A000009 AMERICA EXPRESS CREDIT CORP.
022 B000009 94-1701676
022 C000009 140084
022 D000009 0
022 A000010 ALEX BROWN & SONS, INC.
022 B000010 52-1319768
022 C000010 61604
022 D000010 28339
023 C000000 6922361
023 D000000 595352
024 000000 N
025 D000001 0
025 D000002 0
025 D000003 0
025 D000004 0
025 D000005 0
025 D000006 0
025 D000007 0
025 D000008 0
026 A000000 N
026 B000000 Y
026 C000000 N
026 D000000 Y
026 E000000 N
026 F000000 N
<PAGE> PAGE 4
026 G010000 N
026 G020000 N
026 H000000 Y
027 000000 Y
028 A010000 57113
028 A020000 0
028 A030000 0
028 A040000 44634
028 B010000 73300
028 B020000 0
028 B030000 0
028 B040000 39927
028 C010000 39807
028 C020000 0
028 C030000 0
028 C040000 26230
028 D010000 36081
028 D020000 0
028 D030000 0
028 D040000 27205
028 E010000 43968
028 E020000 0
028 E030000 0
028 E040000 34328
028 F010000 36924
028 F020000 0
028 F030000 0
028 F040000 28517
028 G010000 287193
028 G020000 0
028 G030000 0
028 G040000 200841
028 H000000 287193
029 000000 N
030 A000000 0
030 B000000 0.00
030 C000000 0.00
031 A000000 0
031 B000000 0
032 000000 0
033 000000 0
034 000000 Y
035 000000 810
036 A000000 N
036 B000000 0
037 000000 N
038 000000 0
039 000000 N
040 000000 Y
041 000000 Y
042 A000000 0
<PAGE> PAGE 5
042 B000000 0
042 C000000 100
042 D000000 0
042 E000000 0
042 F000000 0
042 G000000 0
042 H000000 0
043 000000 6461
044 000000 0
045 000000 Y
046 000000 N
047 000000 Y
048 000000 0.000
048 A010000 500000
048 A020000 0.500
048 B010000 0
048 B020000 0.000
048 C010000 0
048 C020000 0.000
048 D010000 0
048 D020000 0.000
048 E010000 0
048 E020000 0.000
048 F010000 0
048 F020000 0.000
048 G010000 0
048 G020000 0.000
048 H010000 0
048 H020000 0.000
048 I010000 0
048 I020000 0.000
048 J010000 0
048 J020000 0.000
048 K010000 500000
048 K020000 0.475
049 000000 N
050 000000 N
051 000000 N
052 000000 N
053 A000000 N
054 A000000 Y
054 B000000 Y
054 C000000 Y
054 D000000 N
054 E000000 N
054 F000000 N
054 G000000 Y
054 H000000 Y
054 I000000 N
054 J000000 Y
054 K000000 N
<PAGE> PAGE 6
054 L000000 Y
054 M000000 Y
054 N000000 N
054 O000000 Y
055 A000000 Y
055 B000000 N
056 000000 Y
057 000000 N
058 A000000 N
059 000000 Y
060 A000000 Y
060 B000000 Y
061 000000 1000
062 A000000 N
062 B000000 0.0
062 C000000 0.0
062 D000000 0.0
062 E000000 0.0
062 F000000 0.0
062 G000000 0.0
062 H000000 0.0
062 I000000 0.0
062 J000000 0.0
062 K000000 0.0
062 L000000 0.0
062 M000000 0.0
062 N000000 0.0
062 O000000 0.0
062 P000000 0.0
062 Q000000 0.0
062 R000000 0.0
063 A000000 0
063 B000000 0.0
066 A000000 Y
066 B000000 N
066 C000000 Y
066 D000000 N
066 E000000 N
066 F000000 N
066 G000000 N
067 000000 N
068 A000000 N
068 B000000 N
069 000000 N
070 A010000 Y
070 A020000 Y
070 B010000 N
070 B020000 N
070 C010000 N
070 C020000 N
070 D010000 N
<PAGE> PAGE 7
070 D020000 N
070 E010000 N
070 E020000 N
070 F010000 N
070 F020000 N
070 G010000 N
070 G020000 N
070 H010000 N
070 H020000 N
070 I010000 N
070 I020000 N
070 J010000 Y
070 J020000 N
070 K010000 N
070 K020000 N
070 L010000 Y
070 L020000 Y
070 M010000 N
070 M020000 N
070 N010000 Y
070 N020000 N
070 O010000 Y
070 O020000 N
070 P010000 Y
070 P020000 N
070 Q010000 N
070 Q020000 N
070 R010000 N
070 R020000 N
071 A000000 1095944
071 B000000 881580
071 C000000 590662
071 D000000 149
072 A000000 12
072 B000000 3546
072 C000000 760
072 D000000 0
072 E000000 0
072 F000000 3194
072 G000000 0
072 H000000 0
072 I000000 893
072 J000000 87
072 K000000 0
072 L000000 78
072 M000000 37
072 N000000 119
072 O000000 4
072 P000000 0
072 Q000000 0
072 R000000 40
<PAGE> PAGE 8
072 S000000 11
072 T000000 6461
072 U000000 0
072 V000000 0
072 W000000 12
072 X000000 10936
072 Y000000 0
072 Z000000 -6630
072AA000000 212478
072BB000000 79648
072CC010000 155317
072CC020000 0
072DD010000 0
072DD020000 0
072EE000000 42761
073 A010000 0.0000
073 A020000 0.0000
073 B000000 1.9212
073 C000000 0.0000
074 A000000 0
074 B000000 5142
074 C000000 9955
074 D000000 0
074 E000000 0
074 F000000 800066
074 G000000 0
074 H000000 0
074 I000000 0
074 J000000 11338
074 K000000 1782
074 L000000 80
074 M000000 37
074 N000000 828400
074 O000000 25507
074 P000000 3521
074 Q000000 0
074 R010000 0
074 R020000 0
074 R030000 0
074 R040000 171
074 S000000 0
074 T000000 799201
074 U010000 28839
074 U020000 0
074 V010000 27.71
074 V020000 0.00
074 W000000 0.0000
074 X000000 82519
074 Y000000 0
075 A000000 0
075 B000000 646141
<PAGE> PAGE 9
076 000000 0.00
077 A000000 Y
077 B000000 Y
077 C000000 N
077 D000000 N
077 E000000 N
077 F000000 N
077 G000000 N
077 I000000 N
077 J000000 N
077 K000000 N
077 L000000 N
077 M000000 N
077 N000000 N
077 O000000 Y
077 P000000 N
077 Q010000 N
077 Q020000 N
077 Q030000 N
078 000000 N
080 A000000 ICI MUTUAL INSURANCE COMPANY
080 B000000 GULF CHUBB VIGILANT RELIANCE
080 C000000 1000000
081 A000000 Y
081 B000000 121
082 A000000 N
082 B000000 0
083 A000000 N
083 B000000 0
084 A000000 N
084 B000000 0
085 A000000 Y
085 B000000 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 SHELDON CURTIS
TITLE VICE PRESIDENT
<TABLE> <S> <C>
<ARTICLE> 6
<LEGEND>
Dean Witter Developing Growth Securities Trust
09-30-1996 annual
</LEGEND>
<CIK> 0000711674
<NAME> DEAN WITTER DEVELOPING GROWTH SECURITIES TRUST
<S> <C>
<PERIOD-TYPE> YEAR
<FISCAL-YEAR-END> SEP-30-1996
<PERIOD-END> SEP-30-1996
<INVESTMENTS-AT-COST> 659,845,328
<INVESTMENTS-AT-VALUE> 815,162,466
<RECEIVABLES> 13,200,346
<ASSETS-OTHER> 36,865
<OTHER-ITEMS-ASSETS> 0
<TOTAL-ASSETS> 828,399,677
<PAYABLE-FOR-SECURITIES> 25,507,131
<SENIOR-LONG-TERM-DEBT> 0
<OTHER-ITEMS-LIABILITIES> 3,692,042
<TOTAL-LIABILITIES> 29,199,173
<SENIOR-EQUITY> 0
<PAID-IN-CAPITAL-COMMON> 532,239,205
<SHARES-COMMON-STOCK> 28,838,582
<SHARES-COMMON-PRIOR> 20,939,667
<ACCUMULATED-NII-CURRENT> (39,118)
<OVERDISTRIBUTION-NII> 0
<ACCUMULATED-NET-GAINS> 111,683,279
<OVERDISTRIBUTION-GAINS> 0
<ACCUM-APPREC-OR-DEPREC> 155,317,138
<NET-ASSETS> 799,200,504
<DIVIDEND-INCOME> 760,163
<INTEREST-INCOME> 3,545,756
<OTHER-INCOME> 0
<EXPENSES-NET> 10,935,513
<NET-INVESTMENT-INCOME> (6,629,594)
<REALIZED-GAINS-CURRENT> 132,830,087
<APPREC-INCREASE-CURRENT> (16,804,216)
<NET-CHANGE-FROM-OPS> 109,396,277
<EQUALIZATION> 0
<DISTRIBUTIONS-OF-INCOME> 0
<DISTRIBUTIONS-OF-GAINS> (42,760,549)
<DISTRIBUTIONS-OTHER> 0
<NUMBER-OF-SHARES-SOLD> 20,988,017
<NUMBER-OF-SHARES-REDEEMED> (14,839,539)
<SHARES-REINVESTED> 1,750,437
<NET-CHANGE-IN-ASSETS> 264,332,000
<ACCUMULATED-NII-PRIOR> (33,774)
<ACCUMULATED-GAINS-PRIOR> 28,274,244
<OVERDISTRIB-NII-PRIOR> 0
<OVERDIST-NET-GAINS-PRIOR> 0
<GROSS-ADVISORY-FEES> 3,194,151
<INTEREST-EXPENSE> 0
<GROSS-EXPENSE> 10,935,513
<AVERAGE-NET-ASSETS> 646,140,751
<PER-SHARE-NAV-BEGIN> 25.54
<PER-SHARE-NII> (0.23)
<PER-SHARE-GAIN-APPREC> 4.32
<PER-SHARE-DIVIDEND> 0
<PER-SHARE-DISTRIBUTIONS> (1.92)
<RETURNS-OF-CAPITAL> 0
<PER-SHARE-NAV-END> 27.71
<EXPENSE-RATIO> 1.69
<AVG-DEBT-OUTSTANDING> 0
<AVG-DEBT-PER-SHARE> 0
</TABLE>
