Two hundred and eighty-two patients with congenital bleeding disorders received blood component replacement therapy between January 1979 and April 1985, were followed-up by the Puget Sound Blood Center's Hemophilia Care Program, and were tested for antibody to human immunodeficiency virus (HIV). Serologic results were obtained at least 1 year after the last exposure to volunteer donor products that were prepared before donor HIV screening or after the last exposure to concentrates produced before the manufacturer's use of treatment methods for inactivation of HIV. In all, 106 patients were anti-HIV positive. The risk of HIV infection was greater in patients with more severe bleeding tendencies, greater exposure to components, and exposure to lyophilized concentrates from large pools of donors. Of 100 patients with hemophilia A who only received cryoprecipitate from volunteer donors from Washington State (during the 6.3-year period), 14% had become anti-HIV positive. Of 27 patients receiving mostly cryoprecipitate but also being exposed to a single lot of concentrate during the same period, 13 (48%) were positive. Of 49 patients treated predominantly or solely with factor VIII concentrates during this period, 43 (88%) were anti-HIV positive. Of 29 patients with von Willebrand disease, four were anti-HIV positive, including 2 of 26 receiving only cryoprecipitate and two of three who had received a single dose of factor VIII concentrate. Of 19 patients who were treated solely with volunteer donor plasma, all remained anti-HIV negative. Of 47 patients exposed to factor IX concentrate, 28 (60%) were positive. Data relevant to the risk of HIV transmission subsequent to screening of the volunteer donor population were also obtained. Treatment records of 55 hemophilia A patients who have remained anti-HIV negative through at least June 1990 showed exposure to 71,173 screened donors from May 1985 through December 1989, and all 55 patients have remained anti-HIV negative.