HIV infection in children presents a wide spectrum of clinical manifestations, from asymptomatic to opportunistic infections, neurologic deterioration and malignancy. This retrospective study describes the characteristics of 30 HIV infected children, attended at the Hospital Infantil de México. Six patients were asymptomatic and 24 symptomatic. Twenty four patients presented a secondary infection, 66% opportunistic infections, compared against the 100% who presented around 3 serious bacterial infections. The most frequent infections were: candidiosis 18 children, pneumonia 14, sepsis 8, cryptosporidiosis 5, urinary tract infection 5, and otitis 5. We were able to demonstrate P. carinii pneumonia in only one patient. These differences in the frequency of related infections may represent regional differences by country.