This paper describes the increasing trends and changing patterns of human immunodeficiency virus (HIV) infection in children occurring since 1982-83 when the first cases were reported worldwide and from 1987-89 when the first cases were detected in Chile. Advances and obstacles dealing with pediatric HIV in Chile are discussed. The most relevant advance is the outstanding reduction in vertical transmission of HIV associated with the implementation of preventive strategies. Risk of vertical transmission has decreased from 35%o in absence of preventive strategies to 2%o with prevention that include maternal and newborn antiretroviral therapy, elective caesarean section and replacement of breast feeding by artificial milk. The main obstacle to further reduce cases has been the delay in implementation of universal screening for pregnant women. This delay has resulted in that currently, the great majority of pediatric HIV cases are detected among symptomatic children. We propose a guideline to detect and appropriately derive pregnant women infected with HIV and children exposed or infected with the virus in order to further reduce the number of children with AIDS in Chile.