ABSTRACT A case of normotensive hyperaldosteronism, with hypokalemic alkalosis and hypergranularity of the juxtaglomerular apparatus, was reported in an adult 24 yr of age. Reduced vascular response to angiotensin and norepinephrine, increased plasma renin activity and renin content of the kidney were clearly demonstrated. Potassium-losing tendency was demonstrated with sodium loading and a positive potassium balance was obtained with salt restriction. Subtotal adrenalectomy was performed with temporary improvement. Pathophysiology and treatment were discussed.