EXHIBIT 21 SIGNIFICANT SUBSIDIARIES OF THE REGISTRANT (as defined in Section 1-02(v) of Regulation S-X) CACI, Inc., a Delaware Corporation CACI, INC.-FEDERAL, a Delaware Corporation CACI, INC.-COMMERCIAL, a Delaware Corporation CACI Products Company, a Delaware Corporation American Legal Services Corp., a Delaware Corporation CACI Field Services, Inc., a Delaware Corporation CACI N.V., a Netherlands Corporation CACI Limited, a U.K. Corporation