Gastric adenomyoma (AM) is a rare benign tumor characterized by gland-like structures embedded within a smooth muscle stroma. We report a case of a 68-yearold man with gastric AM admitted to our hospital for melana. Endoscopic examination revealed a gastric mass of about 4 cm in diameter, located in the antrum. Histologic examination of the excised specimen showed irregularly arranged glands and interlacing smooth muscle bundles surrounding the glandular elements. Although gastric AM is rare, it should be considered in differential diagnosis of extramucosal gastric tumor.