A 66-year-old woman was hospitalized with a 2-month history of vaginal bleeding. Computed tomography and magnetic resonance imaging on admission showed a uterine tumor. The serum alpha-fetoprotein (AFP) level was 16,170 ng/ml (normal < 20). A total hysterectomy with bilateral salpingo-oophorectomy and regional lymphadenectomy were performed. A grayish-white tumor with focal necrotic areas was located in the posterior wall of the corpus uteri with smaller nodules in the lateral wall of the cervix. The tumor had two histologic patterns: one was a well-differentiated endometrioid adenocarcinoma and the other consisted of nests of cells resembling hepatocytes. In the hepatoid areas, giant cells and mitotic figures were frequent. Tumor cells in both the hepatoid areas and the glandular areas were immunoreactive for AFP. The tumor was diagnosed as a hepatoid adenocarcinoma of the uterus, the first described in this site, although 23 cases of hepatoid adenocarcinoma arising in the stomach, lung, kidney, ovary, duodenum, and urinary bladder have been reported.