Record linkage was carried out between the national Registry of AIDS and 13 Cancer Registries (CRs) covering, in 1991, about 15% of the Italian population. Observed and expected numbers of cancers and standardized incidence ratios (SIRs) were assessed in 6067 persons with AIDS, for a total of 25,759 person-years. Significantly increased SIRs were found for Hodgkin's disease [8.9, 95% confidence interval (CI) 4.4-16.0], in which seven of 11 cases were of mixed cellularity type; invasive carcinoma of the cervix uteri (15.5; 95% CI 4.0-40.1); and non-melanomatous skin cancer (3.0, 95% CI 1.3-5.9), in which five of eight cases were basal cell carcinoma. An excess was also seen for brain tumours, but this may be partly due to misdiagnosis of brain non-Hodgkin's lymphoma or other brain diseases occurring near the time of the AIDS diagnosis. The risk for all cancer types, after exclusion of Kaposi's sarcoma (KS) and non-Hodgkin's lymphoma (NHL), was approximately twice the general population risk. An increased SIR for Hodgkin's disease in persons with AIDS is thus confirmed, though it is many times smaller than that for NHL. An association with invasive carcinoma of the cervix is also shown at a population level. The excess of non-melanomatous skin cancer seems to be lower than in transplant recipients.