This analysis evaluated the extent to which infections with selected blood-borne viruses, specifically infection with hepatitis B virus, hepatitis C virus, and/or the human immunodeficiency virus (HIV), continue to contribute to the morbidity of persons with hemophilia. The Georgia Hemophilia Surveillance System collected information on 336 state residents with hemophilia A or B who were followed by a physician in 1994. Data abstracted from medical records included information on demographics, sources of hemophilia care, clinical characteristics, joint range of motion measurements, hospitalization, and results of laboratory testing for hepatitis B, hepatitis C, and the human immunodeficiency virus. Prevalence of infection with one or more of these viruses was determined, and relationships with disease severity, bleeding frequency, and amount of clotting factor prescribed were explored. No child under the age of ten was positive for the human immunodeficiency virus; hepatitis infection was also uncommon in this age group, in contrast to the very high frequency of such infections among older subjects. There was a strong association between HIV positive status and infection with one of the hepatitis viruses. The likelihood of all types of viral infection increased with frequency of bleeding and with amount of clotting factor received. Efforts to prevent transmission of lipidenveloped viruses via clotting factor have been extremely effective. However, currently infected hemophilia patients will likely experience significant morbidity and mortality due to chronic liver disease and AIDS-related complications. Am.