Objective: To evaluate the incidence of hypogonadism in men with metabolic syndrome and its correlation with serum insulin levels. Methods: Observational, transversal study with 80 men with metabolic syndrome. The individuals were divided into two groups: Group 1: 56 patients (70%) with total testosterone ≥ 300 ng/dL (normal gonadal function); Group 2: 24 patients (30%) with total testosterone < 300 ng/dL (hypogonadic). Results: The subjects from Group 2 compared to Group 1 presented higher body mass index (BMI), waist and hip circumferences, insulin, homeostasis model assessment insulin resistance index (Homa-IR) and beta cell (Homa-β), and triglycerides, but lower SHBG and free testosterone values. Inverse correlations between insulin levels and total testosterone and SHBG, as well as between Homa-IR and total testosterone were observed. Conclusion: In this series of men with metabolic syndrome, hypogonadism was associated with insulin resistance and may be a marker of metabolic abnormalities. Arq Bras Endocrinol Metab. 2009;53(8):1005-11