A record linkage was carried out between the Italian National Registry of AIDS and 19 cancer registries. The aim was to evaluate the 1986 through 1998 trends in incidence rate (IR) of AIDS-defining cancers (ADCs) among persons with AIDS (PWA) in Italy overall and according to various characteristics. A steady decrease in IRs was found for Kaposi sarcoma (KS) in men between 1986-1992 (2.5 per 100 person-years [py]) and 1997-1998 (1.0 per 100 py). Conversely, the first decrease in IRs of KS in women (from 0.9 to 0.6 per 100 py) and of non-Hodgkin lymphoma in both genders (from 1.7 to 0.7 per 100 py) was seen between 1993-1996 and 1997-1998, thus pointing to a favorable impact of highly active antiretroviral therapies. The decline was consistent across different age and HIV transmission groups, but it was more marked in PWA with a CD4 count >50 cells/microL than in PWA with more severe immune suppression. As a proportion of AIDS cases, invasive cervical cancer increased from 1.5% in 1993-1996 to 2.4% in 1997-1998, but IRs after AIDS could not be evaluated. On account of the marked decline of KS in men in 1997-1998, the overall burden of ADCs in Italy became similar in both genders.