In a health examination survey of more than 2,000 middle-aged men the prevalence of hypertension, defined as supine DBP greater than or equal to 105 mmHg and including those on treatment, was 7.5%. Half of the hypertensives were untreated. A satisfactory BP control was present in 27.6% of the total hypertensive population. Untreated hypertensives had a higher relative body weight and a greater skinfold thickness, indicating a greater degree of obesity, than a population sample from the same survey. They also had more hyperuricaemia, hypertriglyceridaemia and hyperinsulinaemia, fasting as well as during i.v. glucose tolerance test. However, when the hypertensives were compared to normotensive, weight-matched controls, most of these differences were eliminated. The findings indicate that the metabolic disturbances in hypertensives are associated with overweight and suggest that weight reduction might be beneficial not only for the BP but also for correcting the metabolic pattern.