We compared corticosteroid metabolite excretion rates and patterns in a group of 68 subjects with untreated essential hypertension and a matched group of 48 normotensive control subjects. The ratio of tetrahydrocortisol plus allotetrahydrocortisol to tetrahydrocortisone and the ratio of allotetrahydrocortisol to tetrahydrocortisol were significantly higher in the hypertensive group. This is qualitatively similar to the situation found in patients with the syndrome of apparent mineralocorticoid excess or subjects treated with licorice or carbenoxolone where hypertension is known to arise from deficiencies of 11 beta-hydroxysteroid dehydrogenase and 5 beta-reductase activities. The equivalent ratios for corticosterone metabolites were not different between groups, but total corticosterone metabolite excretion was higher in the hypertensive group. Plasma cortisol levels were lower in hypertensive than in control subjects, but corticosterone levels were higher. This evidence supports a previous suggestion that the activities of these two enzymes may be reduced in essential hypertension, but the contribution of these changes to hypertension is not known.