AIM To document the impact that rapid increases in HIV infection in hospitalised children at Chris Hani Baragwanath Hospital has had on in-hospital mortality. METHODS Hospital discharge summaries from January 1992 to the end of 1996 were reviewed. RESULTS There were 20 733 admissions in the five year period; 7985 (39%) were tested for HIV. In tested admissions above 15 months of age, 4.9% were HIV infected in 1992, increasing to 35% in 1996. Under 15 months of age, 9% of tested admissions were positive in 1992, increasing to 46% in 1996. The proportion of all hospital deaths occurring in children considered HIV infected (ELISA testing together with clinical features if 15 months or younger) increased from 6.7% in 1992 to 46.1% in 1996 (p < 0.001). In-hospital mortality for all children increased by 21% from 4.3% in 1992 to 5.2% in 1996. Mortality rates declined in uninfected children from 5.4% in 1992 to 4.5% in 1996 (χ2 trend 3.3; p = 0.06). CONCLUSION The mortality rate of children has increased at Chris Hani Baragwanath Hospital as a result of HIV infection. Almost half the deaths were HIV related in 1996. HIV infection is threatening the advances that have been made on child survival in South Africa over the last few decades.