This is a comprehensive presentation of schistosomiasis in a cross section of the indigenous population of South Central Africa, primarily the area around Salisbury, Southern Rhodesia, but also including native laborers of Northern Rhodesia, Portuguese Africa and Nyasaland, who come to Southern Rhodesia every year in search of work. The study provides minimum necessary information on the biology and epidemiology of the two etiologic agents, Schistosoma haematobium and S. mansoni, and is concerned for the most part with the pathology of these diseases and their symptomatology. It is based on several hundred cases studied by the author over a ten-year period on the medical wards, in the mortuary and in the public health laboratory at Salisbury. These infections are highly prevalent in the area, much more common as revealed by autopsy section than examination of feces and urine would indicate.Contrary to current views, Doctor Gelfand has found that S. mansoni is easier to detect than is S. haematobium unless careful post-mortem study is conducted.