Few studies have documented the contribution of HIV/AIDS to mortality among children under 15 years. From June 30 to October 19, 2001, all child deaths (n=588) registered to the morgue and/or hospitals of the city of Pointe-Noire, Congo, were investigated using a combined approach including an interview of relatives and postmortem clinical and biological HIV diagnosis. Twenty-one percent of children were HIV positive, while 10.5 of deaths were attributed to AIDS. The most common causes of death in HIV-infected children were pneumonia (30), pyrexia (22), diarrhoea (16) and wasting syndrome (16). Infant mortality rate was estimated 6.3 times higher in children born to HIV-infected mothers compared to HIV-uninfected mothers. This study provides a direct measure of HIV/AIDS as impact on child mortality using a rapid and reliable method. A significant number of deaths could be prevented if HIV infection was diagnosed earlier and infants were provided with antiretroviral treatments. Copyright © 2010 Camille Lallemant et al.