Progression from seroconversion to the development of AIDS in Africa may be shorter than in industrialized countries, but there are insufficient data to be certain. Although the data are not always directly comparable, survival after an AIDS diagnosis appears to be substantially shorter in African countries and this may be partly because of later diagnosis of AIDS in Africa, but may also be because of environmental factors such as increased exposure to pathogens of high virulence and lack of access to care. Tuberculosis and bacterial infections are the most important causes of morbidity and mortality among hospitalized patients. Bacteraemia is frequent, particularly due to non-typhoid salmonellae and S. pneumoniae. Cryptosporidia and I. belli are the most frequently isolated pathogens in patients with diarrhoea; non-typhoid salmonellae and Shigella species are also commonly isolated when stool cultures are performed. Cerebral toxoplasmosis, and meningitis due to Cryptococcus, tuberculosis and bacterial pathogens are the most frequent neurological infections and cognitive changes are frequently identified when specifically looked for. Infections with atypical mycobacteria and Pneumocystis carinii are rare, as is CMV retinitis. In women, HIV infection is associated with cervical human papillomavirus and with SIL, although there is currently no evidence for an association with invasive cervical cancer. Individuals infected with HIV-2 progress to AIDS and to death more slowly than those infected with HIV-1, but seem to experience the same spectrum of opportunistic disease when they reach the stage of advanced disease. The limited data available suggest that HIV-infected individuals in Africa develop opportunistic disease at broadly the same level of immunosuppression as do individuals in industrialized countries, but death occurs at a higher range of CD4 counts, although still in the range consistent with advanced disease. Data are still lacking concerning the aetiology of common clinical presentations of HIV disease and the relative frequencies of specific opportunistic diseases in different regions, particularly from southern Africa. Tuberculosis is the single most important HIV-related opportunistic infection in African countries, but diagnosis, particularly of extrapulmonary disease, remains difficult. The lack of laboratory facilities makes the diagnosis of bacterial infections difficult in many parts of the continent and, since this situation is unlikely to change in the near future, clinical algorithms for syndromic management need to be evaluated. More information is needed about gynaecological disease in HIV-infected women. The most important research questions concern the development and evaluation of cost-effective regimes for prophylaxis and treatment of opportunistic disease in order to prolong healthy life in HIV-infected individuals.