The typical onset of schizophrenia during late adolescence and early adulthood has stimulated interest in the potential contribution of hypothalamo-pituitary-gonadal (HPG) axis abnormalities to this disorder. Previous investigations of reproductive hormone function in men with schizophrenia suggest diminished activity of the HPG axis. These studies have been hampered, however, by methodologic limitations. We have attempted to address these limitations by rigorous determination of gonadotropin and gonadal hormone levels, and attention to demographic and diagnostic variables. In contrast to prior studies, our results indicate that schizophrenic patients do not show statistically significant differences from healthy volunteers with respect to luteinizing hormone pulsatility, response to gonadotropin-releasing hormone challenge, and testosterone secretion. Due to the small number of subjects, however, these findings must be regarded as preliminary and warrant further study.