A case of disseminated Pneumocystis carinii (PC) infection in a 28-year-old Japanese male hemophiliac with acquired immunodeficiency syndrome (AIDS) is reported. The patient had displayed a high fever and diffuse faint interstitial infiltrates on chest X-ray films without dyspnea three months before his death. At that time, no PC was detected after four consecutive induced sputum tests. Serum anti-cytomegalovirus (CMV) IgM was positive by EIA. No treatment for PC and CMV was given at the patient's request. Autopsy findings disclosed disseminated PC infection consisting of granulomas with caseation-like, necrosis and frothy exudate in the lungs and disseminated organized calcification in the blood vessels of extrapulmonary organs. PC cysts and/or trophozoites were detected in these lesions.