This 3 cm adrenal adenoma was discovered in a patient with Conn syndrome (primary aldosteronism). Aldosterone-producing adrenal adenoma is the cause in 70% of patients with primary aldosteronism. Most of the remainder are seen in the setting of adrenal cortical hyperplasia. Adrenal cortical carcinoma is the etiology in only rare cases of primary aldosteronism. Elevated aldosterone levels cause excessive potassium loss in urine (causing hypokalemia), sodium retention, hypertension, and suppression of plasma renin levels. When primary aldosteronism is suspected, a thorough evaluation of renin-angiotensin-aldosterone axis should be done along with radiographic evaluation of both adrenals. In cases of adenoma, surgical resection is usually curative.