The influence of testosterone and estrogen on memory was investigated in 33 healthy young men. Tests of visual memory, visuospatial ability, verbal memory, and attention were administered, and circulating levels of estradiol and free testosterone were measured. Participants with high levels of estradiol performed better on 2 measures of visual memory than did those with normal but lower levels. There were no differences between individuals with high and low levels of testosterone on any cognitive measure. These results support the contention that estradiol influences memory in young men.