Patients with AIDS frequently present with pulmonary complications which are associated with a high mortality rate and infections are the most important cause of lung infiltrates. In addition to pneumonia caused by Pneumocystis carinii, which was noted in early reports of the syndrome, a variety of other severe pulmonary disorders may occur. Frequently more than one organism is found in a single patient and among these, combined infections of Pneumocystis carinii and cytomegalovirus are the most common. We experienced a case of combined Pneumosytis carinii and Mycobacterium tuberculosis infection as a pulmonary manifestation of AIDS in a 38-year-old man. In bronchoalveolar larvage, bronchial washing and brushing, and sputum smear specimens, Pneumocystis carinii organisms were recognized, especially in Gomori's methenamine silver stains. Transbronchial lung biopsy specimen revealed intra-alveolar frothy exudates composed of collections of Pneumocystis carinii organisms as well as several granulomas with central caseous necroses.