Primary aldosteronism, which is characterized by hypertension, hypokalemia and hyperaldosteronemia resulting from chronic oversecretion of aldosterone independent of normal renin-angiotensin regulatory system, is an uncommon disease in Korea. At present overall incidence of this disorder is considered to be 1-2% of all hypertensive patients. With wide availability of technical analysis of aldosterone and renin activity, it is easy to detect the primary aldosteronism with certainty. Differential diagnosis between aldosterone-producing adenoma and idiopathic hyperaldosteronism is essential, because surgical therapy is effective only in primary aldosteronism due to adenoma. We experienced a case of primary aldosteronism with adrenocortical adenoma, which was diagnosed by clinical data, computed tomographic scan and adrenal venogram. Surgical adrenalectomy was very successful for control of hypertension and clinical symptoms.