A total of 121 acquired immunodeficiency syndrome (AIDS) patients diagnosed in Haiti were studied between June 1979 and December 1983. Risk factors were identified in 65% of 34 patients evaluated in a standardized manner since July 1983 and included: bisexuality, 38%; blood transfusion, 21%; and intravenous drug abuse or a spouse with AIDS, 6%. These risk factors were reported by only 20% of the 85 patients studied between June 1979 and June 1983. AIDS patients also re ported more frequent parenteral injections prior to the onset of their illness than control subjects (e.g., siblings, friends, sexual partners). Heterosexual activity among female AIDS patients was also greater than in their female controls. It was concluded that, in contrast to the experience reported among Haitians with AIDS in the USA, risk factors are present among most patients with AIDS in Haiti.