Two outbreaks of botulism in sheep and goats are described; in one, 329 out of 900 sheep in a feedlot died within 9 d of the onset of the disease and in the other, 100 sheep and goats out of 330 succumbed over a period of about 3 weeks. Animals were found dead or died suddenly, without exhibiting clinical signs. Others stood with lowered heads and showed drooling of saliva or a stiff gait. Paresis and/or paralysis were frequent signs in the terminal stages of the disease. Gross lesions such as the accumulation of fluids in body cavities, pulmonary oedema, foam in the trachea, epicardial haemorrhages and congestion of the mucosa of the small intestine, suggestive of heart failure, were present in animals from both outbreaks. Botulism was confirmed via the mouse toxicity test, by the demonstration of Type C and Type D toxins in the feed and intestinal contents of sheep from the first outbreak and Type D toxin in intestinal contents of sheep from the second. The clinical signs and macropathology in the outbreaks of botulismin sheep and goats in South Africa may resemble ''krimpsiekte'' and cardiac glycoside and ionophore poisoning, as well as other conditions causing heart failure.