This survey of the fisheries of Lake Rukwa, Tanganyika, describes results obtained during 1963-1964, and includes comparative material given by previous workers, in particular surveys conducted in 1936 by Ricardo and, in 1946 by Swynnerton. Data is given on the general hydrology of the Lake including chemical analyses, seasonal and annual fluctuations of volume. Cyclical variations of lake level occur every 20/30 years and the level now reaching a new maximum is expected to fall again during the next decade. The record of fish species from the Rukwa basin is enlarged by 3 genera: Polypterus, Protopterus and Chiloglanis; a summary of the biology and commercial exploitation of 20 species of fish is given. An historical account of the fish production from the lake and its subsequent marketing concludes that in 1963/64 some 5,328 tons of dried fish products are marketed annually; between 10-6;10 of this trade is directed towards the Rhodesias and the remainder is absorbed within Tanganyika. The state of the indigenous fishing enterprise is discussed, and for the improvement of the industry recommendations are given that the marketing of fish products should be immediately investigated and encouraged both abroad and within, Tanganyika. Further suggestions include the improvement of water-transport on the lake, the development of improved fishing-craft, fishing-methods, processing methods and further investigation of the biology of the fish-fauna.