AIDS and HIV infection are now endemic in many parts of Africa. The infection is mainly transmitted by heterosexual activity, as illustrated by a 1:1 female to male case ratio and high HIV seroprevalence rates in people at risk for sexually transmitted diseases and female prostitutes. Transmission by blood transfusions, contaminated injections and from mother to child is occurring more frequently than in Europe. AIDS will probably have a profound impact on health care programmes and economic development in the continent, and its control should be a public health priority.