The paper reviews much of the literature relating to the major bacterial, viral and fungal diseases of cassava and presents this together with additional information gained by the authors. The importance of these diseases in reducing yields of this important source of carbohydrate is stressed. However, while much information is presented on symptoms and nature of the pathogens, little data is available on control measures. The authors emphasise the need for more active research, in particular into identifying and describing sources of disease resistance and into other simple means of disease control.