The study defines the epidemiological characteristics of HIV-infection in the population of Genoa and estimates the entity of AIDS-cancer association. The cohort includes 317 subjects resident in the Municipality of Genoa, aged above 14 years and notified prior to 31 December 1991 and/or dead from AIDS in the period 1988-1991. From 1984 to 1991, 44 cases of tumour were recorded. The comparison between the rate ratios found in the AIDS patients' cohort and in the general population of Genoa strengthen the significant association highlighted in literature regarding overall cancer, 26.7 (p < 0.05), and in particular, Kaposi's sarcoma, 3239.4 (p < 0.05); non-Hodgkin's lymphomas, 84.8 (p < 0.05); Hodgkin's lymphomas, 20.6 (p < 0.05). Moreover, a significant increase in the risk of testicular seminoma, 61.5 (p < 0.05) and lung cancer, 18.0 (p < 0.05) is confirmed.