Two hundred fourteen hospitalized adult men, aged 27 to 92, were examined for the presence of palpable gynecomastia. The overall prevalence was 65 percent. Gynecomastia was bilateral in all but 11 subjects. The prevalence was greatest in the 50 to 69-year-old group (72 percent). It was lower in the 70- to 89-year-old (47 percent, p < 0.01) and the 30- to 49-year-old (54 percent, p < 0.05) groups. The prevalence of gynecomastia increased with body mass Index. More than 80 percent of those with a body mass Index of 25 kg/m2 or greater had gynecomastia. The diameter of breast tissue also increased with increasing body mass index (r = 0.52, p < 0.001). The decreased prevalence of gynecomastia after the seventh decade could be explained by the lower body mass index in this group. The youngest group did not have a lower body mass index; an independent age factor appeared to be present. Because of the high overall prevalence of gynecomastia, independent effects of diseases or medications could not be determined. It is concluded that palpable bilateral gynecomastia is present in most older men, is correlated with the amount of body fat, and does not require clinical evaluation unless symptomatic or of recent onset.