Reported cases of acquired immunodeficiency syndrome (AIDS) in San Francisco as of March 31, 1986, include 92 individuals who had donated blood subsequent to 1978. Their donated blood components had been transfused into 406 different recipients. The current status of 336 of these recipients was ascertained as of April 1, 1986. Of these, 223 had died at the time of our first contact, almost all as a result of the condition for which they were transfused. Seven had developed AIDS; five of these died, two before entry into the study and three subsequently. Forty-six additional living recipients were interviewed and evaluated. Seven had the AIDS-related complex, 18 had antibody to the human immunodeficiency virus (HIV) but were otherwise healthy, and 19 had no detectable anti-HIV. Two had risk factors other than transfusion. The frequency of infection of the recipient decreased as the time interval between transfusion and the diagnosis of AIDS in the donor increased. This information should be useful when counseling patients who have been transfused with blood components from donors later found to be infected with HIV.