<ARTICLE> 5
<LEGEND>
This schedule contains summary financial information extracted from the
Unaudited Consolidated Financial Statements of ADE Corporation for the nine
months ended January 31, 2000 and is qualified in its entirety by reference
to such financial statements.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          APR-30-2000
<PERIOD-START>                             MAY-01-1999
<PERIOD-END>                               JAN-31-2000
<CASH>                                          33,306
<SECURITIES>                                         0
<RECEIVABLES>                                   12,043
<ALLOWANCES>                                     (621)
<INVENTORY>                                     28,272
<CURRENT-ASSETS>                                86,886
<PP&E>                                          29,721
<DEPRECIATION>                                (14,577)
<TOTAL-ASSETS>                                 133,402
<CURRENT-LIABILITIES>                           16,921
<BONDS>                                         12,094
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           133
<OTHER-SE>                                     104,254
<TOTAL-LIABILITY-AND-EQUITY>                   133,402
<SALES>                                         42,563
<TOTAL-REVENUES>                                42,563
<CGS>                                           25,379
<TOTAL-COSTS>                                   25,379
<OTHER-EXPENSES>                                34,158
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               (841)
<INCOME-PRETAX>                               (16,133)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                           (16,133)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                  (17,571)
<EPS-BASIC>                                     (1.32)
<EPS-DILUTED>                                   (1.32)