Primary aldosteronism (PA) has long been considered a rare disease, but a higher prevalence was suggested recently. The aim of this study was to evaluate the prevalence of PA in a group of Bulgarian hypertensive patients, including patients with adrenal incidentalomas (AI). The aldosterone to renin ratio (ARR)>750 was used as a positive screening test and the Captopril test was performed to confirm the diagnosis. Adrenal CT scan was used to differentiate between the main subtypes of PA- aldosterone-producing adenoma (APA) and idiopathic hyperaldosteronism (IHA). The diagnosis of APA was retrospectively confirmed after surgery. After excluding other forms of endocrine hypertension, except PA, we investigated a total of 472 consecutive hypertensive patients, among them 96 patients with AI. Final diagnosis of PA was reached in 38 patients (8.05%) in the entire hypertensive population and in 12 patients (12.5%) among hypertensive patients with AI. In the group of PA, 15 patients (39.5%) were diagnosed with APA and 23 patients (60.5%) had an IHA. Among all patients with PA 21 (55.3 %) presented with hypokalemia. Our findings of a relatively high prevalence of PA support an early diagnosis of this potentially curable disease, especially in hypertensive patients with AI.