The role of the renin-angiotensin-aldosterone system (RAAS) in hypertension has since long been recognized and aldosterone has been acknowledged as one of the key hormones in the pathophysiology, not only in primary aldosteronism but also in essential hypertension and drug-resistant hypertension. Aldosterone-receptor antagonists (ARAs) are increasingly used in patients with resistant hypertension, often with impressive results. However, definitive evidence for the benefit of ARAs in these patients from randomized, controlled trials is lacking. This review gives an overview of the current data on this topic. Future studies should focus on the identification of factors that are able to predict the response to treatment, as to select patients who will benefit most from treatment with ARAs. On the basis of the current knowledge, we recommend prescription of ARAs to patients with primary aldosteronism, resistant hypertension and patients with hypertension and hypokalemia.