Patients admitted to hospitals in tropical Africa are at increased risk for nosocomial infection. However accurate description of this risk is difficult due to a lack of published data in the literature. The main promoting factors are poor health care facilities, high microbial levels in the hospital and community environment and generally uncertain health status. Most available information is about neonatal infection. The increasing number of reports involving multiresistant bacteria is evidence of poor hospital sanitation. Infections involving operative incision sites, tuberculosis and respiratory virus transmission are grossly underestimated. Infections transmitted by the parenteral route are probably decreasing due to more widespread use of disposal equipment and adequate transfusion safety measures. Epidemics involving viral hemorrhagic fever are rare but highly publicized events that attest to daily neglect of nosocomial risk factors in some health care facilities