Normotensive hyperaldosteronism is a rare disorder. It is usually diagnosed with hypokalemia or an adrenal mass. Our patient was a 27-year-old female presented with weakness. She had normal blood pressure, hypokalemia, high plasma aldosterone level and suppressed plasma renin activity. After the saline load, test aldosterone didn’t show suppression. Adrenal computed tomography revealed a left adrenal mass. The patient was treated with spironolactone and potassium supplement. Surgical adrenalectomy was done. Final pathologic diagnosis was benign adrenocortical adenoma without capsular invasion. In postoperative course serum, potassium was normal.