The nature and extent of the environmental effects of insecticides applied in tsetse control/eradication operations depend on the actual insecticide used and the mode of application. A comparison of the impact of insecticides with that of previous control methods, e.g. bush clearing and game destruction, shows that the latter produce a greater impact. Rural development, which is not necessarily dependent on tsetse eradication, also produces environmental changes, and the impact of tsetse control/eradication by insecticide application should not be considered in isolation.