To determine the types of pulmonary disease associated with human immunodeficiency virus (HIV) infection, we conducted a prospective study of 302 consecutive patients admitted for acute respiratory disease to a university hospital in Bujumbura, Burundi. Diagnoses were made according to well-defined criteria. Of the total, 222 patients (73.5%) were HIV seropositive, with women younger than men. Features suggestive of underlying HIV infection were the clinical findings of oral thrush, peripheral lymphadenopathy, or herpes zoster and the radiographic abnormalities of hilar-mediastinal adenopathy or a reticulonodular infiltrate. Tuberculosis and community-acquired pneumonia occurred with approximately equal frequency in the HIV-seropositive and seronegative groups. Pneumocystis carinii pneumonia was diagnosed in 11 patients, all seropositive. Gram-negative bacteremia, especially Salmonella typhimurium, occurred in 23 seropositive patients (10.4%). A total of 24 seropositive patients died during the initial hospitalization, and 11 others required readmission; no seronegative patients died or were rehospitalized. We conclude that HIV infection is a major risk factor for the development of acute respiratory diseases in adults of sufficient severity to require hospitalization in Bujumbura. In this Central African country, where exposure to virulent bacterial pathogens is ubiquitous, tuberculosis, pneumonia, and salmonellosis occur with much greater frequency than classic AIDS-defining opportunistic infections or malignancies.