To review the experience of the Immunodeficiency Clinic of the Department of Infectious Diseases at Hospital Infantile de México "Federico Gómez", in the management of children with HIV infection and AIDS. the medical records of 130 patients with a clinical and laboratory diagnosis of HIV/AIDS seen between September 1985 and June 1994 were reviewed. Data was obtained regarding diagnosis, epidemiological risk factors, clinical features, types and numbers of bacterial and opportunistic infections, malignancies, hospitalizations, general and specific treatment and outcome. The diagnosis followed CDC guidelines and was established in all 130 patients serologically with ELISA and Western Blot. In infants < 18 months, diagnosis was made by detection of p24 and/or viral culture in two separate occasions. Data from 130 subjects was obtained; 74 were male and 56 female for a M:F ratio of 1.3:1. With regards to mode of transmission, 62.3% was vertical, 20.8% post transfusion, 8.5% hemophiliacs (the latter two males were cases before occurred 1987), 6.2% sexual and 2.2% unknown. With regards to additional risk factors, in 35 cases the parents were heterosexual, in 18 one parent had a history of transfusion, and in eight the father was bisexual. According to the CDC classification; 16 had indeterminate infection or PO; nine were asymptomatic or P1; and 105 were symptomatic or P2. Eighty two patients had nonspecific findings, 60 had neurologic manifestations, 18 had lymphocytic interstitial pneumonia and four had secondary malignancies. It was possible to document 296 episodes of secondary infections: 154 bacterial, 58 opportunistic, and 84 with other pathogens. in Mexico, as in other Western countries, vertical transmission has become the dominant form of acquiring HIV infection in children, reflecting a change in the epidemiology of infection in women of child bearing age. Moreover, since IV drug use is a very limited phenomenon in Mexico, heterosexual transmission is the major form of transmission in women.