<TABLE> <S> <C>
<PAGE>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE BALANCE
SHEET AND INCOME STATEMENT OF TYCO INTERNATIONAL LTD. AS OF AND FOR THE QUARTER
ENDED DECEMER 31, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 3-MOS
<FISCAL-YEAR-END> SEP-30-2000
<PERIOD-START> OCT-01-1999
<PERIOD-END> DEC-31-1999
<CASH> 1,230,100
<SECURITIES> 0
<RECEIVABLES> 5,634,900
<ALLOWANCES> 361,000
<INVENTORY> 3,069,800
<CURRENT-ASSETS> 11,137,300
<PP&E> 14,037,200
<DEPRECIATION> 6,152,700
<TOTAL-ASSETS> 34,805,900
<CURRENT-LIABILITIES> 9,375,900
<BONDS> 10,514,600
0
0
<COMMON> 338,600
<OTHER-SE> 12,821,300
<TOTAL-LIABILITY-AND-EQUITY> 34,806,800
<SALES> 6,638,800
<TOTAL-REVENUES> 6,638,800
<CGS> 4,191,900
<TOTAL-COSTS> 4,191,900
<OTHER-EXPENSES> 0
<LOSS-PROVISION> 7,200
<INTEREST-EXPENSE> 182,400
<INCOME-PRETAX> 1,019,300
<INCOME-TAX> 262,100
<INCOME-CONTINUING> 757,200
<DISCONTINUED> 0
<EXTRAORDINARY> (200)
<CHANGES> 0
<NET-INCOME> 757,000
<EPS-BASIC> 0.45
<EPS-DILUTED> 0.44
</TABLE>