The extent of the risk of AIDS transmission through the blood supply in Africa is not known. The alarming prevalence of AIDS in some zones and the significant proportion of medical and surgical conditions requiring blood transfusions make it imperative that an AIDS control strategy be developed that is adapted to local possibilities. Posttransfusional AIDS is hard to document because other modes of contamination may have caused the infection and because past blood donors are often difficult to locate. Only the confirmation of infection in the donor provides sufficient evidence to incriminate posttransfusional AIDS. In the US, some 45,000 persons probably received infected blood transfusions before screening became obligatory, and in France the frequency of seropositivity is .6/1000. In Europe 5.6% of AIDS cases are believed to have been acquired through blood transfusions. According to some estimates, 5-10% of the African population carry the AIDS virus. 4 measures are essential in protecting the blood supply: 1) donors belonging to groups at risk of AIDS should be excluded. In Africa, prostitutes far outnumber intravenous drug users and homosexuals. The difficulty is that this recommendation depends on the candor of potential blood donors. 2) Each blood donation should be systematically screened for AIDS antibodies 3) Seropositive donors should be informed of their infection in strict confidence by a physician and informed of the modes of transmission of AIDS and their ability to infect others. Their sexual partners should be encouraged to undergo AIDS screening. Seropositive women should be informed of the risks of pregnancy to themselves and to their future offspring. 4) Coagulation factors and plasma should undergo viral inactivation through heat or other means as a final safeguard.