During 6 months, 506 consecutive adult emergency admissions to hospital in Nairobi were enrolled in a study of bacteraemia and HIV infection. 19% were HIV-1 antibody positive. Significantly more HIV-seropositive than seronegative patients had bacteraemia (26% vs 6%). The predominant organisms isolated from the seropositive patients were Salmonella typhimurium and Streptococcus pneumoniae. Mortality was higher in the seropositive than in the seronegative bacteraemic patients. The findings suggest that non-opportunistic bacteria are important causes of morbidity and mortality in HIV-infected individuals in Africa.