Cutaneous Kaposi's sarcoma (KS) is a well-known complication of the acquired immunodeficiency syndrome. KS in the internal organs, however, is rare in Japan. We present here a 33-years-old Japanese homosexual man who had AIDS complicated with cytomegalovirus (CMV) infection and KS. He was found to be HIV-seropositive, when he was 31-years-old. He visited our hospital in June 1996 because of high fever. The peripheral blood CD4+ lymphocyte counts were 2 per cubic millimeter, and CMV antigenemia was noted (p65 antigen positive cells; 240/50,000 white blood cells). Thereafter he was successfully treated with parental ganciclovir. On admission, some brown-colored flat nodules were found on the skin, and the diagnosis of KS was made by skin biopsy. We administrated human chorionic gonadotropin (hCG) for the treatment of KS, but had no clinical response. In September 1996, he complained of severe cough, shortness of breath, and vomiting. A chest radiogram showed nodular lesions and pleural effusion in bilateral lungs. A computed tomography of his chest also revealed nodular and linear densities distributed along the bronchovascular bundles. The ultrasonic examination of his abdomen revealed a duodenal nodule. Both nodules in the lungs and duodenum were proved to be KS based on the autopsy findings. Intranuclear inclusionbodies pathognomonic for CMV infections were detected in the stomach and the colon.