Primary hyperaldosteronism (PHA) is the most frequent cause of secondary hypertension (HT). Furthermore, it is associated with greater cardiometabolic and mortality risk than the observed in patients with essential HT. It is recommended to screen for PHA by determining the aldosterone-to-renin ratio in patients with severe and/or resistant HT, HT with hypokalemia, HT and adrenal incidentaloma, HT and a first-degree family history of PHA, and in HT associated with atrial fibrillation that cannot be explained by other causes. If a pathological aldosterone-to-renin ratio is confirmed, dynamic tests should be performed to establish a confirmatory diagnosis; these are usually a saline infusion test or captopril challenge test. These tests can be omitted in patients with overt PHA (plasma aldosterone greater than 20 ng/dl, suppressed renin, and hypokalemia). The last step in the diagnosis is the localization study, being the computed tomography (CT) scan of the adrenal glands the initial test of choice. Nevertheless, in most patients in whom adrenal surgery is considered, adrenal vein sampling (AVS) will be necessary to establish PHA laterality. AVS is not considered necessary in cases of suspected aldosterone-producing adrenocortical carcinoma and/or PHA in patients younger than 35 years with a clear unilateral lesion on a CT/magnetic resonance imaging (MRI) test. The treatment of PHA depends on the results of the localization study: the treatment of choice is a unilateral adrenalectomy in unilateral forms and mineralocorticoid receptor antagonists in bilateral forms.