It is now well established that testosterone levels decline with age. What has not been established is whether the decline in testosterone is associated with a symptom complex. This study examined whether certain symptoms are more commonly present in males with low bioavailable testosterone (BT) levels. These were used to evaluate a questionnaire for androgen deficiency in aging males (ADAM). The validity of the ADAM questionnaire to screen for low BT was tested in 316 Canadian physicians aged 40 to 62 years. Low BT levels were present in 25% of this population. None had elevated luteinizing hormone (LH) levels. The ADAM questionnaire had 88% sensitivity and 60% specificity. When the questionnaire was administered twice 2 to 4 weeks apart to 10 men, it was determined that the coefficient of variation was 11.5%. In a second study of 34 ADAM-positive patients, 37% of those with clearly normal BT levels demonstrated some evidence of dysphoria. Finally, in 21 patients who were treated with testosterone, improvement on the ADAM questionnaire was demonstrated in 18 (P = .002). These data support the concept of a symptom complex associated with low BT levels in aging males. In addition, the ADAM questionnaire appears to be a reasonable screening questionnaire to detect androgen deficiency in males over 40 years of age.