To determine the recent trends in AIDS-defining cancers in Western Europe, we analyzed the June 2002 European Non-Aggregate AIDS Data Set. We obtained the percentage of people with AIDS aged 15 years or older (n = 125,691; males, 99,560, females, 26,131) who had cancers as the initial AIDS-defining illness in 17 European countries. Overall, from 1994 through 2001, declines were noted in the number of people with AIDS (25,324 to 8929), the proportion of people with AIDS who were homosexual/bisexuals (38.8% to 26.6%) or intravenous drug users (male, 41.7% to 34.8%; female, 50.2% to 26.4%). Among males, between 1994 and 2001, the percentage with any AIDS-defining, cancers declined (14.4% to 13.1%, p for trend = 0.091) because of a decline in Kaposi's sarcoma (KS; 10.7% to 7.9%) mostly among homosexual/bisexual men (22.7% to 18.8%) (p for trends < 0.05). Between 1994 and 2001, the percentage of males with all types of lymphomas increased (3.8% to 5.2%, p for trend = 0.012). Among females, AIDS-defining cancers increased (7.3% to 8.5%) due to increase in lymphomas (all types, 2.6% to 4.0%) (p for trend = 0.05). Cervical cancer remained the most common cancer among females, the percentage of which declined between 1994 and 2001 (2.8% to 2.0%, p for trend = 0.37) mostly among women who were 15 to 29 years old, most of whom acquired HIV heterosexually. In summary, declines were noted for the two leading AIDS-defining cancers at initial AIDS diagnosis among certain population groups. KS declined among men who had sexually transmitted HIV infection. Cervical cancer declined among young females and heterosexuals.