The plasma glucose, immunoreactive insulin, and growth hormone levels after a 50-g oral glucose load have been measured in 15 adult Bushmen subjects living in the Kalahari region of Southern Africa. Compared with 10 non-obese white controls, they showed relative glucose intolerance and significantly impaired insulin secretion. Growth hormone responses showed no significant differences between the two groups. Factors such as inadequate or unusual nutrition and stress do not appear to account completely for the abnormalities in carbohydrate metabolism observed in the Bushmen. Of interest are the clinical and hormonal similarities that seem to exist between the Bushmen and the Central African Pygmies.