Gout is commonly associated with obesity, arterial hypertension, diabetes, and dyslipidemia. However, the prevalence of metabolic syndrome has not been widely recognized in patients with gout. We studied 41 patients (37 males) with primary gout to assess the prevalence and characteristics of the associated metabolic syndrome. Twenty-one patients with gout (51%) showed >or=3 criteria for the metabolic syndrome. Pathological conditions associated were obesity (21/41), high blood pressure (30/41), dyslipidemia (30/41), and fasting plasma glucose >or= 100 mg/dL (22/41). The most frequent triad was the presence of increased waist circumference, elevated fasting plasma glucose, and hypertension. Mean serum urate concentration did not differ significantly in gout patients with the metabolic syndrome (8.5 mg/dl) and without (8.1 mg/dl). Given the complications associated with metabolic syndrome, its diagnosis may determine the long-term treatment of patients with gout.