We report the cases of 38 children with transfusion-associated HIV infection: 18 hemophiliacs and 2 patients with Von Willebrand disease, 6 with hemoglobinopathies, 8 with malignant diseases or aplastic anemia, 2 transfused during neonatal period and 2 during a surgical operation. Two groups with a different prognosis were found: In group A [hemophilia and Von Willebrand disease (n = 20)] 17 patients were asymptomatic or only with lymphadenopathy; 3 reached stage IV and none died. In group B [Others (n = 14)] 2 patients were asymptomatic, 4 reached stage IV and 8 died, 4 of them directly from AIDS. The difference between both groups was statistically significant. Prognosis of HIV infection is particularly severe in patients with leukemia, malignant tumors and aplastic anemia.