<PAGE> PAGE 1
000 B000000 05/31/98
000 C000000 0000783740
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 MFS SERIES TRUST X
001 B000000 811-4492
001 C000000 6179545000
002 A000000 500 BOYLSTON STREET
002 B000000 BOSTON
002 C000000 MA
002 D010000 02116
003 000000 N
004 000000 N
005 000000 N
006 000000 N
007 A000000 Y
007 B000000 3
007 C010100 1
007 C010200 2
007 C020200 MFS INTERNATIONAL GROWTH AND INCOME FUND
007 C030200 N
007 C010300 3
007 C020300 MFS INTERNATIONAL GROWTH FUND
007 C030300 N
007 C010400 4
007 C020400 MFS/F&C EMERGING MARKETS EQUITY FUND
007 C030400 N
007 C010500 5
007 C010600 6
007 C010700 7
007 C010800 8
007 C010900 9
007 C011000 10
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008 C00AA01 801-17352
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008 D03AA01 02116
008 A00AA02 FOREIGN & COLONIAL MANAGEMENT LTD.
008 B00AA02 S
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008 D01AA02 LONDON
008 D05AA02 ENGLAND
008 D06AA02 EC2A 2NY
008 A00AA03 FOREIGN & COLONIAL EMERGING MARKETS LIMITED
<PAGE> PAGE 2
008 B00AA03 S
008 C00AA03 801-000000
008 D01AA03 LONDON
008 D05AA03 ENGLAND
008 D06AA03 EC2A 2NY
010 A00AA01 MASSACHUSETTS FINANCIAL SERVICES COMPANY
010 B00AA01 801-17352
010 C01AA01 BOSTON
010 C02AA01 MA
010 C03AA01 02116
011 A00AA01 MFS FUND DISTRIBUTORS, INC.
011 B00AA01 8-27864
011 C01AA01 BOSTON
011 C02AA01 MA
011 C03AA01 02116
012 A00AA01 MFS SERVICE CENTER, INC.
012 B00AA01 84-1316
012 C01AA01 BOSTON
012 C02AA01 MA
012 C03AA01 02116
013 A00AA01 ERNST & YOUNG LLP
013 B01AA01 BOSTON
013 B02AA01 MA
013 B03AA01 02116
015 A00AA01 STATE STREET BANK AND TRUST COMPANY
015 B00AA01 C
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015 C02AA01 MA
015 C03AA01 02110
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015 B00AA02 S
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015 E04AA02 X
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<PAGE> PAGE 3
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<PAGE> PAGE 4
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<PAGE> PAGE 5
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<PAGE> PAGE 6
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<PAGE> PAGE 7
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<PAGE> PAGE 8
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<PAGE> PAGE 9
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<PAGE> PAGE 10
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<PAGE> PAGE 11
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025 A000301 DELETE
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<PAGE> PAGE 12
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<PAGE> PAGE 13
063 B000300 0.0
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<PAGE> PAGE 14
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<PAGE> PAGE 15
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<PAGE> PAGE 16
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<PAGE> PAGE 17
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<PAGE> PAGE 18
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<PAGE> PAGE 19
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SIGNATURE MARK E. BRADLEY
TITLE ASSISTANT TREASURER
WARNING: THE EDGAR SYSTEM ENCOUNTERED ERROR(S) WHILE PROCESSING THIS SCHEDULE.
<TABLE> <S> <C>
<ARTICLE> 6
<CIK> 0000783740
<NAME> MFS SERIES TRUST X
<SERIES>
<NUMBER> 041
<NAME> MFS/FOREIGN & COLONIAL EMERGING MARKETS EQUITY FUND CLASS A
<MULTIPLIER> 1
<S> <C>
<PERIOD-TYPE> YEAR
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<PERIOD-START> JUN-01-1997
<PERIOD-END> MAY-31-1998
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<INVESTMENTS-AT-VALUE> 79340576
<RECEIVABLES> 1279190
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