Primary aldosteronism (PA) is the most common cause of endocrine hypertension with a high frequency of cardiovascular complications. We found in our previous study higher occurrence of metabolic disturbances in patients with idiopathic hyperaldosteronism (IHA) compared to subjects with aldosterone-producing adenoma (APA). The aim of our present study is to evaluate potential differences in the frequency of end-organ damage (arterial stiffness and microalbuminuria) between two main types of PA. The diagnosis of the particular form of PA was based on adrenal venous sampling and/or histopathological examination. We analyzed clinical and laboratory data from 72 patients with PA (36 with IHA, 36 with APA). The arterial stiffness was expressed as the carotid-femoral pulse wave velocity (PWV) and the renal damage as urinary albumin excretion levels (UAE). Patients with IHA had significantly (p<0.03) higher prevalence of metabolic syndrome (17 % in APA, 35 % in IHA), higher triglycerides (1.37+/-0.71 mmol/l in APA, 1.85+/-0.87 mmol/l in IHA), lower HDL cholesterol (1.25+/-0.28 mmol/l in APA, 1.06+/-0.25 mmol/l in IHA), higher PWV (7.91+/-1.61 m/s in APA, 8.99+/-1.77 m/s in IHA) and higher UAE (12.93+/-2.21 mg/l in APA, 28.09+/-6.66 mg/l in IHA). It seems that patients with IHA may have a slightly different phenotype compared to APA.