Body fat, body cell mass, fasting blood sugar, glucose tolerance and fasting insulin have been determined in 106 hypertensive males aged 47-54years and in 41 normotensive 50-year-old males. Both groups were derived from screening examinations in random population samples. The hypertensive subjects were more often obese and had more often an impaired glucose tolerance and a higher fasting insulin compared with the normotensive subjects. The metabolic differences were not explained simply by the higher degree of obesity in the hypertensive subjects, as the differences remained when the hypertensive subjects were matched for body fat with normotensive controls. The impaired glucose metabolism demonstrated quantitatively in an unselected group of hypertensive subjects, might be one of the factors explaining the variable prognosis in hypertensive subjects.