Ten patients with hypertension and obesity were studied during a program of weight loss on an unrestricted sodium diet. The study showed that weight loss during the ten month period was accompanied by a significant decrease in urinary aldosterone, tetrahydroaldosterone −3-glucuronide and plasma renin activity values. It was also demonstrated that successful reduction in body weight was associated with a reduction in blood pressure. It is postulated that blood pressure reduction in obese patients during weight reduction may depend on decreases in aldosterone and plasma renin activity. The reduction in levels of tetrahydroaldosterone-3-glucuronide is due to an energy related depression of the glucuronidation process caused by carbohydrate deficiency. It is postulated that the lowered rate of metabolism of aldosterone as measured by the diminished formation of the metabolite tetrahydroaldosterone-3-glucuronide is an important determinant of blood pressure status during weight reduction.