Three questionnaires, the St. Louis University Androgen Deficiency in Aging Male (ADAM), the Aging Male Survey (AMS) and the Massachusetts Male Aging Study (MMAS), have been developed as potential screening tools for hypogonadism in older males. We compared these questionnaires in 148 males aged 23-80 years using bioavailable testosterone as the "biochemical gold standard" for diagnosis of hypogonadism. The sensitivity for the ADAM was 97%, for the AMS 83% and the MMAS 60%. Specificity was 30% for the ADAM, 59% for the MMAS and 39% for AMS. Both bioavailable testosterone and the calculated free testosterone correlated significantly with a number of the individual questions. Total testosterone correlated poorly with most of the questions. In conclusion, the ADAM and AMS may be useful screening tools for hypogonadism across the adult lifespan, but both are relatively nonspecific.