Approaching the fiftieth year since its original description, primary aldosteronism is now thought to be the commonest potentially curable and specifically treatable form of hypertension. Correct identification of patients with primary aldosteronism requires that the effects of time of day, posture, dietary sodium intake, potassium levels and medications on levels of aldosterone and renin be carefully considered. Accurate elucidation of the subtype is essential for optimal treatment, and adrenal venous sampling is the only reliable means of differentiating aldosterone-producing adenoma from bilateral adrenal hyperplasia. With genetic testing already available for one inherited form, making more cumbersome biochemical testing for that subtype virtually obsolete and bringing about improvements in treatment approach, an intense search is underway for genetic mutations causing other, more common familial varieties of primary aldosteronism.