The purpose of this study is to clarify the clinical and pathologic features of endometrial carcinomas in women 65 years of age or older in Japan where the incidence of endometrial carcinoma is still low. Between 1979 and 1990, 24 of 164 patients with endometrial carcinoma were 65 years old or over. In addition, 41 patients 50 years of age or younger were also analyzed, comparing clinicopathologic features with those of older age group. Seventeen of 24 (71%) showed deep myometrial invasion (more than a half of the myometrium). Endometrial carcinomas in older age groups have deeper myometrial invasion, and higher histologic grade than those of younger age groups. The adjacent endometrium is usually atrophic and the presence of hyperplasia and/or metaplasia was significantly less frequent in the older group as compared with that in the younger group. Nine of these 24 patients died of disease in a relatively short follow-up period. The prognosis for the older group (expected 5-year survival 69.2%) is significantly worse than for the younger group (expected 5-year survival 94.3%) (P = 0.006). Endometrial carcinomas in patients over 65 years of age are usually of high histologic grade, and have deep myometrial invasion and an unfavorable prognosis.