Rhipicephalus appendiculatus Neum. occurs mainly in the eastern and southern parts of Africa and is the principal cause and vector of some very important stock diseases in these areas. The diseases include the theilerioses, brown tick toxicosis and Nairobi sheep disease. These are briefly discussed, and emphasis is laid on the role of R. appendiculatus in their epidemiology. R. appendiculatus is a 3-host tick particularly well adapted to survive where climate and vegetation are suitable. The basic requirements and breeding potential of this tick are also discussed.