Thirty-three children vertically infected with human immunodeficiency virus type 1 (HIV-1), who were born before 1985, were followed in a single center, and had reached the age of 6 years, were studied and tested for school achievement. Of these 33 children, 24 were also tested for cognitive abilities, fine motor and language skills, and emotional adaptation. Of the 33 patients, 22 (67%) had normal school achievement at a mean age of 9.5 +/- 1.6 years. The mean IQ was 95 +/- 11, but 54% of the patients (13/24) had abnormal results on visual-spatial and time orientation tests, 44% had speech and/or language delay or articulation disorders, and 29% of the children and 42% of the parents had psychoaffective disturbances of intermediate or high severity. Normal school performance was positively correlated with results of the different cognitive tests and to a lesser extent with the absence of psychoaffective symptoms, but was independent of the mode of maternal infection or the parents' educational level. Children with normal school achievement had a higher percentage of circulating CD4+ lymphocytes during the course of infection. We conclude that children whose HIV-1 infection is maternally acquired have better cognitive abilities and school achievement than was initially thought, and that the percentage of circulating CD4+ lymphocytes during the first years of life appears to be predictive of future school adaptation or cognitive abilities.