The Baltimore Longitudinal Study of Aging examined the influence of aging and androgens (total testosterone, dehydroepiandrosterone sulfate, sex hormone-binding globulin (SHBG)) on metabolic syndrome prevalence (based on NCEP-ATP III criteria). Metabolic syndrome prevalence was 4, 21, 21, and 18% for men 20-39, 40-59, 60-79, and 80-94 years of age, respectively. Total testosterone and SHBG were inversely related to the metabolic syndrome over the 5.8 years of follow-up, while the free testosterone index (total testosterone/SHBG) and BMI were positively related to metabolic syndrome incidence. Age alone did not predict the metabolic syndrome. Among androgens, SHBG was found to have the greatest influence on development of the metabolic syndrome.