PAGE 1 000 B000000 10/31/2015 000 C000000 0001275214 000 D000000 N 000 E000000 NF 000 F000000 Y 000 G000000 Y 000 H000000 N 000 I000000 6.1 000 J000000 A 001 A000000 CALAMOS STRATEGIC TOTAL RETURN FUND 001 B000000 811-21484 001 C000000 6302457200 002 A000000 2020 CALAMOS COURT 002 B000000 NAPERVILLE 002 C000000 IL 002 D010000 60563 003 000000 N 004 000000 N 005 000000 N 006 000000 N 007 A000000 N 007 B000000 0 007 C010100 1 008 A000001 CALAMOS ADVISORS LLC 008 B000001 A 008 C000001 801-29688 008 D010001 NAPERVILLE 008 D020001 IL 008 D030001 60563 010 A000001 State Street Bank and Trust Company 010 B000001 028-00733 010 C010001 Boston 010 C020001 MA 010 C030001 02111 012 A000001 COMPUTERSHARE 012 B000001 85-05006 012 C010001 College Station 012 C020001 TX 012 C030001 77842 012 C040001 3170 013 A000001 Deloitte & Touche LLP 013 B010001 Chicago 013 B020001 IL 013 B030001 60606 014 A000001 CALAMOS FINANCIAL SERVICES LLC 014 B000001 8-37854 015 A000001 STATE STREET BANK & TRUST COMPANY 015 B000001 C 015 C010001 BOSTON 015 C020001 MA 015 C030001 02111 PAGE 2 015 E010001 X 015 A000002 EUROCLEAR BANK 015 B000002 S 015 C010002 BRUSSELS 015 D010002 BELGIUM 015 E040002 X 015 A000003 DEUTSCHE BANK PARIS 015 B000003 S 015 C010003 PARIS 015 D010003 FRANCE 015 E040003 X 018 000000 Y 019 A000000 Y 019 B000000 27 019 C000000 CALAMOSINV 020 A000001 JPMORGAN CHASE SECURITIES, INC. 020 B000001 13-3224016 020 C000001 83 020 A000002 GOLDMAN SACHS & CO. 020 B000002 13-5108880 020 C000002 44 020 A000003 CITIGROUP, INC. 020 B000003 11-2418191 020 C000003 33 020 A000004 BARCLAYS CAPITAL, INC 020 B000004 61-031656 020 C000004 31 020 A000005 BTIG, LLC 020 B000005 04-3695739 020 C000005 21 020 A000006 CREDIT SUISSE FIRST BOSTON 020 B000006 13-2853402 020 C000006 18 020 A000007 INVESTMENT TECHNOLOGY GROUP, INC. 020 B000007 95-2848406 020 C000007 12 020 A000008 SANFORD C. BERNSTEIN & CO., LLC 020 B000008 13-4132953 020 C000008 11 020 A000009 JONESTRADING INSTITUTIONAL SERVICES LLC 020 B000009 51-0484896 020 C000009 9 020 A000010 MORGAN STANLEY & CO., INC. 020 B000010 13-2655998 020 C000010 8 021 000000 300 022 A000001 JPMORGAN CHASE SECURITIES, INC. 022 B000001 13-3224016 022 C000001 60833 022 D000001 51652 022 A000002 CREDIT SUISSE FIRST BOSTON PAGE 3 022 B000002 13-2853402 022 C000002 45188 022 D000002 47835 022 A000003 JEFFERIES & COMPANY, INC. 022 B000003 95-2622900 022 C000003 30270 022 D000003 50001 022 A000004 BANK OF AMERICA 022 B000004 56-0906609 022 C000004 48055 022 D000004 28537 022 A000005 BARCLAYS CAPITAL INC. 022 B000005 94-3231066 022 C000005 23668 022 D000005 27101 022 A000006 WELLS FARGO ADVISORS LLC 022 B000006 34-1542819 022 C000006 12451 022 D000006 18082 022 A000007 GOLDMAN SACHS & CO. 022 B000007 13-5108880 022 C000007 21865 022 D000007 5266 022 A000008 CITIGROUP, INC. 022 B000008 11-2418191 022 C000008 2210 022 D000008 24070 022 A000009 ROYAL BANK OF CANADA 022 B000009 56-1688522 022 C000009 7984 022 D000009 9804 022 A000010 MORGAN STANLEY & CO., INC. 022 B000010 13-2655998 022 C000010 8268 022 D000010 4353 023 C000000 281858 023 D000000 296048 024 000000 Y 025 A000001 CITIGROUP, INC. 025 B000001 11-2418191 025 C000001 E 025 D000001 50246 025 A000002 JPMORGAN CHASE SECURITIES, INC. 025 B000002 13-3224016 025 C000002 E 025 D000002 51079 025 A000003 BANK OF AMERICA 025 B000003 56-0906609 025 C000003 E 025 D000003 8390 025 A000004 JEFFERIES & COMPANY, INC. PAGE 4 025 B000004 95-2622900 025 C000004 D 025 D000004 5920 025 A000005 WELLS FARGO ADVISORS LLC 025 B000005 34-1542819 025 C000005 E 025 D000005 61269 026 A000000 N 026 B000000 Y 026 C000000 N 026 D000000 Y 026 E000000 N 026 F000000 N 026 G010000 N 026 G020000 N 026 H000000 N 027 000000 N 028 A010000 0 028 A020000 0 028 A030000 0 028 A040000 0 028 B010000 0 028 B020000 0 028 B030000 0 028 B040000 0 028 C010000 0 028 C020000 0 028 C030000 0 028 C040000 0 028 D010000 0 028 D020000 0 028 D030000 0 028 D040000 0 028 E010000 0 028 E020000 0 028 E030000 0 028 E040000 0 028 F010000 0 028 F020000 0 028 F030000 0 028 F040000 0 028 G010000 0 028 G020000 0 028 G030000 0 028 G040000 0 028 H000000 0 030 A000000 0 030 B000000 0.00 030 C000000 0.00 031 A000000 0 031 B000000 0 PAGE 5 032 000000 0 033 000000 0 035 000000 0 036 B000000 0 038 000000 0 042 A000000 0 042 B000000 0 042 C000000 0 042 D000000 0 042 E000000 0 042 F000000 0 042 G000000 0 042 H000000 0 043 000000 0 044 000000 0 045 000000 Y 046 000000 N 047 000000 Y 048 000000 1.000 048 A010000 0 048 A020000 0.000 048 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 0 048 K020000 0.000 049 000000 N 050 000000 N 051 000000 N 052 000000 N 053 A000000 N 054 A000000 Y 054 B000000 Y 054 C000000 N 054 D000000 N 054 E000000 N PAGE 6 054 F000000 N 054 G000000 N 054 H000000 Y 054 I000000 N 054 J000000 Y 054 K000000 N 054 L000000 N 054 M000000 Y 054 N000000 N 054 O000000 N 055 A000000 N 055 B000000 Y 056 000000 Y 057 000000 N 058 A000000 N 059 000000 Y 060 A000000 Y 060 B000000 Y 061 000000 0 062 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 N 066 D000000 N 066 E000000 N 066 F000000 N 066 G000000 Y 067 000000 N 068 A000000 N 068 B000000 N 069 000000 N 070 A010000 Y PAGE 7 070 A020000 N 070 B010000 Y 070 B020000 Y 070 C010000 Y 070 C020000 N 070 D010000 Y 070 D020000 N 070 E010000 Y 070 E020000 N 070 F010000 Y 070 F020000 N 070 G010000 Y 070 G020000 N 070 H010000 Y 070 H020000 N 070 I010000 Y 070 I020000 N 070 J010000 Y 070 J020000 Y 070 K010000 Y 070 K020000 Y 070 L010000 Y 070 L020000 Y 070 M010000 Y 070 M020000 Y 070 N010000 Y 070 N020000 Y 070 O010000 Y 070 O020000 Y 070 P010000 Y 070 P020000 N 070 Q010000 N 070 Q020000 N 070 R010000 Y 070 R020000 N 071 A000000 559605 071 B000000 674276 071 C000000 2459614 071 D000000 23 072 A000000 12 072 B000000 43005 072 C000000 48723 072 D000000 0 072 E000000 250 072 F000000 25938 072 G000000 0 072 H000000 0 072 I000000 27 072 J000000 65 072 K000000 0 072 L000000 243 PAGE 8 072 M000000 139 072 N000000 34 072 O000000 0 072 P000000 6305 072 Q000000 446 072 R000000 107 072 S000000 206 072 T000000 0 072 U000000 0 072 V000000 0 072 W000000 278 072 X000000 33787 072 Y000000 0 072 Z000000 58191 072AA000000 44452 072BB000000 726 072CC010000 0 072CC020000 78141 072DD010000 102618 072DD020000 0 072EE000000 0 073 A010000 0.6600 073 A020000 0.0000 073 B000000 0.0000 073 C000000 0.3300 074 A000000 33 074 B000000 0 074 C000000 601 074 D000000 732716 074 E000000 178323 074 F000000 1483654 074 G000000 0 074 H000000 0 074 I000000 191465 074 J000000 59432 074 K000000 0 074 L000000 11011 074 M000000 331 074 N000000 2657566 074 O000000 135194 074 P000000 2434 074 Q000000 716000 074 R010000 0 074 R020000 0 074 R030000 0 074 R040000 912 074 S000000 0 074 T000000 1803026 074 U010000 154514 074 U020000 0 074 V010000 11.67 PAGE 9 074 V020000 0.00 074 W000000 0.0000 074 X000000 92 074 Y000000 1202227 075 A000000 0 075 B000000 1862470 076 000000 10.20 077 A000000 Y 077 B000000 Y 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 A000000 ICI MUTUAL INSURANCE COMPANY 080 C000000 15000 081 A000000 Y 081 B000000 39 082 A000000 Y 082 B000000 100 083 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 PAGE 10 087 A010000 COMMON STOCK 087 A020000 128125101 087 A030000 CSQ 088 A000000 N 088 B000000 N 088 C000000 Y 088 D000000 N SIGNATURE CURTIS HOLLOWAY TITLE TREASURER