PIP: 4 cases of Pneumocystis carinii pneumonia in HIV-infected patients studied at the University of Zambia Medical School, Lusaka, were verified by bronchoalveolar lavage. Pneumocystis is common in North American AIDS patients, but has been considered rare in Africa. One reason may be that facilities for diagnosis, bronchoscopy with bronchoalveolar lavage, are not usually available. 44 consecutive HIV seropositive patients who were unresponsive to a 10-day course of antibiotics, and whose sputum was negative for acid fast bacteria, underwent bronchoalveolar lavage from February 1990 to December 1990. HIV status was assayed with Welcozyme ELISA kits, and P. carinii was detected with toluidine blue O stain. The 1st case of confirmed P. carinii pneumonia was a 35-year old man who had a productive cough for 4 weeks, fever, and dyspnea. He was treated with co-trimoxazole and was symptom-free in 3 weeks, but developed severe Stevens-Johnson reaction. His cultures were positive for M. tuberculosis at week 8. He was lost to follow-up. The 2nd case was a 26-year old man with a 6-month history of cough and white sputum, treated without effect with antituberculous medication. He improved over 3 weeks with co-trimoxazole, but died of respiratory failure 2 months later. The 3rd case was a 30-year old woman being treated for pulmonary tuberculosis, who became progressively dyspneic 7 months later. She developed a generalized maculo-papular rash after taking co-trimoxazole, so was given dapsone 100 mg/day, prednisone 1 mg/kg/day, and trimethoprim 15 mg/kg for 1 week. She improve in 3 weeks. The 4th case was a 30-year old man with a 4-week history of dry cough and dyspnea and recent high fever. He was given co-trimoxazole, but developed generalized purpura after 5 days. His treatment was changed to Dapsone 100 mg/day, prednisone 1 mg/kg/day, and antituberculous medication. He improved after 3 weeks, and is being maintained on Fansidar 1 tablet/week. These cases are remarkable because 2 of them also had pulmonary tuberculosis, which is often the presumed diagnosis of pneumonia in African AIDS patients. Furthermore, 3 developed serious drug reactions to co-trimoxazole, also considered an uncommon occurrence.