<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 SEPTEMBER
27, 1997 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL
STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          APR-04-1998
<PERIOD-END>                               SEP-27-1997
<CASH>                                           3,271
<SECURITIES>                                    35,228
<RECEIVABLES>                                   66,424
<ALLOWANCES>                                     3,674
<INVENTORY>                                      2,899
<CURRENT-ASSETS>                               154,621
<PP&E>                                         139,512
<DEPRECIATION>                                  50,682
<TOTAL-ASSETS>                                 364,283
<CURRENT-LIABILITIES>                           76,827
<BONDS>                                        151,842
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         1,958
<OTHER-SE>                                      94,544
<TOTAL-LIABILITY-AND-EQUITY>                   364,283
<SALES>                                         17,330
<TOTAL-REVENUES>                               153,680
<CGS>                                           14,735
<TOTAL-COSTS>                                  123,627
<OTHER-EXPENSES>                                   435
<LOSS-PROVISION>                                   223
<INTEREST-EXPENSE>                               5,699
<INCOME-PRETAX>                                  6,249
<INCOME-TAX>                                     2,911
<INCOME-CONTINUING>                              2,899
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     2,899
<EPS-PRIMARY>                                      .16
<EPS-DILUTED>                                        0