['To determine the association between hypogonadal symptoms and total serum testosterone levels in middle-aged and elderly men (aged > 40 years), and to identify whether there exists a clear-cut discriminatory threshold of total testosterone below which the probability of hypogonadal symptoms increases.', "We retrospectively reviewed the charts of 360 men who presented to an outpatient men's health clinic with a chief complaint of low testosterone. Sexual, psychological, and physical symptoms were evaluated using the androgen deficiency in the aging male (ADAM) questionnaire. Serum levels of total testosterone were collected on the same day on which men completed their ADAM questionnaires. We performed the univariate (t test, chi-square, and binary logistic regression) and multivariate analyses (binary logistic regression) to evaluate the total testosterone threshold and the symptoms that predicted a low-testosterone level.", 'A cluster of symptoms: 1 sexual (decreased libido), 1 psychological (decreased energy), and 3 physical (decreased strength or endurance, decreased ability to play sports, and falling asleep after dinner) were most associated with total serum testosterone levels of ≤ 300 ng/dL. The threshold testosterone serum levels that were associated with an increased prevalence of these hypogonadal symptoms ranged from 320 to 375 ng/dL. On multivariate analysis, age, but not symptoms on the ADAM questionnaire, predicted a total testosterone level of < 300 ng/dL.'] Are hypogonadal symptoms associated with different serum testosterone thresholds in middle-aged and elderly men?