Primary aldosteronism (PA) is one of the commonest forms of curable hypertension, and use of the plasma aldosterone-to-renin ratio as a screening test has led to a more efficient identification of this condition. Both animal and human studies have indicated that PA is associated with a variety of cardiovascular and renal complications that reflect the capability of elevated aldosterone to induce tissue damage exceeding that induced by hypertension itself. Involvement of the kidney in PA is highly relevant because structural renal damage is associated with less favorable outcome, both in terms of blood pressure response to treatment and possibility to develop progressive renal failure. However, early involvement of the kidney in PA is characterized by functional changes that are largely reversible with treatment. Unilateral adrenalectomy or administration of mineralocorticoid receptor antagonists are the current options for treating an aldosterone-producing adenoma or idiopathic adrenal hyperplasia. Both treatments are effective in correcting hypertension and hypokalemia, and currently available information on their capability to prevent deterioration of renal function indicates that both surgery and medical treatment are of considerable value.