An association between primary aldosteronism and metabolism disorders has been reported. The aim of this retrospective study was to test for this association by comparison between large cohorts of patients with primary aldosteronism and with essential hypertension. We retrieved the records of 460 cases with primary aldosteronism (103 lateralized, 150 not lateralized, and 207 undetermined) and of 1363 controls with essential hypertension individually matched for age and sex. We compared clinical history; blood pressure levels; body mass index; levels of fasting plasma glucose and serum triglycerides; total, high-density lipoprotein, and low-density lipoprotein cholesterol; and the prevalence of diabetes mellitus and impaired fasting glucose among subtypes of primary aldosteronism, as well as between cases with primary aldosteronism and their matched controls. Fasting plasma glucose and serum lipid levels did not differ among the 3 subtypes of primary aldosteronism. The prevalence of impaired fasting glucose was lower in patients with primary aldosteronism than their matched controls, but the prevalence of hyperglycemia (impaired fasting glucose or diabetes mellitus) and blood levels of glucose and lipids did not differ between cases and controls. There was no significant difference between preoperative and postoperative levels of either fasting plasma glucose or serum lipids in patients who underwent adrenalectomy and had follow-up data available. The analysis of this large group of patients with primary aldosteronism and essential hypertension does not confirm a higher prevalence of carbohydrate or lipid metabolism disorders in the former. It is unlikely that the prevalence of metabolic syndrome differs significantly between patients with primary aldosteronism and those with essential hypertension.