The assumption is currently made by international organisations that individuals of the same size living in the same environment and having the same mode of living will have the same energy requirements whatever their race. Reports of very low energy intakes are frequently doubted. To investigate possible racial differences the energy cost of standardised activities was measured in European, Asian, and African males under the same experimental conditions. Subjects were closely matched for height, weight and Quetelet index. The energy cost of each activity, lying, sitting and standing, was significantly higher, by 10–17%, in Europeans as compared to Asians and Africans, between whom no differences were found. Whether these differences are morphological or metabolic is discussed. It is concluded that differences in energy requirements do exist over and above those due to body size and activity.