Sex-typed cognitive abilities were assessed in 33 hypogonadal men receiving testosterone replacement therapy, 10 eugonadal men receiving testosterone in a male contraceptive clinical trial, and 19 eugonadal men not administered testosterone. Prior to and following hormone administration, men completed four tests measuring visuospatial ability, three tests measuring verbal fluency, two tests measuring perceptual speed, and a measure of verbal memory. Group differences in testosterone levels were unrelated to performance on most cognitive measures, including visuospatial ability. Relative to other men, hypogonadal men were impaired in their verbal fluency and showed improved verbal fluency following treatment with testosterone. These data suggest that testosterone may enhance verbal fluency in hypogonadal men and support the general hypothesis that current levels of testosterone may influence some aspects of cognitive function.