<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO
TERRATECH INC.'S QUARTERLY REPORT ON FORM 10-Q FOR THE QUARTER ENDED JANUARY 3,
1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          APR-04-1998
<PERIOD-END>                               JAN-03-1998
<CASH>                                          25,887
<SECURITIES>                                    33,566
<RECEIVABLES>                                   68,336
<ALLOWANCES>                                     3,721
<INVENTORY>                                      1,259
<CURRENT-ASSETS>                               156,645
<PP&E>                                         136,068
<DEPRECIATION>                                  48,142
<TOTAL-ASSETS>                                 369,375
<CURRENT-LIABILITIES>                           79,004
<BONDS>                                        152,553
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         1,958
<OTHER-SE>                                      96,104
<TOTAL-LIABILITY-AND-EQUITY>                   369,375
<SALES>                                         17,330
<TOTAL-REVENUES>                               227,555
<CGS>                                           14,735
<TOTAL-COSTS>                                  183,501
<OTHER-EXPENSES>                                   644
<LOSS-PROVISION>                                   381
<INTEREST-EXPENSE>                               8,371
<INCOME-PRETAX>                                 10,478
<INCOME-TAX>                                     4,915
<INCOME-CONTINUING>                              4,555
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     4,555
<EPS-PRIMARY>                                      .25
<EPS-DILUTED>                                      .24