Six hundred twenty‐four cases of Kaposi's sarcoma occurring in Ugandan Africans have been reviewed. Thirty‐four patients came to necropsy, and almost all were found to have visceral lesions. Patients with nodular cutaneous disease usually had a long history of disease and often had small numbers of visceral nodules which only very seldom produced symptoms. Locally aggressive tumors occurred more commonly in Ugandans than in whites; in spite of locally destructive growth, they seldom metastasized widely and were often present for many years. Young people with generalized involvement were seen rarely and most of these patients had had malaria. The pattern of disease was of two types: in African children, tumor was found predominantly in nodes, whereas in young adults involvement of skin nodes and viscera was seen. The prognosis in such cases was poor. Africans seem to be less likely to develop a second neoplasm than whites. Females suffer from Kaposi's sarcoma less frequently than males but are relatively more likely to develop rapidly fatal generalized forms of the disease.