<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM MCDERMOTT
INTERNATIONAL'S SEPTEMBER 30, 1999 FINANCIAL STATEMENTS AND IS QUALIFIED IN ITS
ENTIRETY BY REFERENCE TO SUCH STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-END>                               SEP-30-1999
<CASH>                                         108,552
<SECURITIES>                                   116,077
<RECEIVABLES>                                  464,578
<ALLOWANCES>                                    63,974
<INVENTORY>                                    218,812
<CURRENT-ASSETS>                             1,405,692
<PP&E>                                       1,448,464
<DEPRECIATION>                               1,012,593
<TOTAL-ASSETS>                               3,895,008
<CURRENT-LIABILITIES>                        1,251,040
<BONDS>                                        323,162
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        61,443
<OTHER-SE>                                     758,567
<TOTAL-LIABILITY-AND-EQUITY>                 3,895,008
<SALES>                                      1,243,754
<TOTAL-REVENUES>                             1,243,754
<CGS>                                        1,183,579
<TOTAL-COSTS>                                1,183,579
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              25,173
<INCOME-PRETAX>                                 47,587
<INCOME-TAX>                                    23,926
<INCOME-CONTINUING>                             23,661
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    23,661
<EPS-BASIC>                                       0.40
<EPS-DILUTED>                                     0.40