There are numerous case reports on psychoses in AIDS patients and, although more seldom, also in HIV-positive patients in early stages of infection; however, systematic investigations on the frequency, e.g., relevant for the indication of an HIV test in psychiatric patients, are missing. For this study, 1046 HIV-positive patients were examined regarding psychoses. A total of 301 patients (28.8%) were HIV-positive but asymptomatic, and 380 patients (36.2%) had the lymphadenopathy syndrome. One hundred thirty-two patients (12.6%) suffered from an AIDS-related complex and 233 patients (22.3%) from AIDS. Of these 1046 patients, only 9 (0.9%) suffered from psychoses. One patient with a paranoid-hallucinatory syndrome was asymptomatic; one in the lymphadenopathy syndrome was manic. The other 7 patients were all in late stages of the infection. A causal relationship between HIV infection and psychosis and probable in only 3 patients. These data do not indicate a markedly elevated prevalence of psychosis in HIV-positive or AIDS patients.