EXHIBIT 21 NIELSEN MEDIA RESEARCH, INC. ACTIVE SUBSIDIARIES AS OF JANUARY 31, 1999 STATE OR OTHER NAME JURISDICTION OF INCORPORATION % OWNERSHIP - ---- ----------------------------- ----------- CZT/ACN Trademarks, L.L.C. ............. Delaware 50% Nielsen Media Research Ltd. ............ Nova Scotia 100% NMR Investing I, Inc. .................. Delaware 100% NMR Licensing Associates, L.P. ......... Delaware 78.53% - --Athenian Leasing Corporation ......... Delaware 100%