Carcinoid tumors generally appear as yellow/gray or tan submucosal nodules. We experienced a case of pedunculated rectal carcinoid showing a mushroom-like appearance. The case was a forty years old woman who was admitted to our hospital due to rectal bleeding. Colonoscopy revealed a pedunculated polyp presenting a mushroom-shaped appearance measuring 13 mm in diameter in the rectum. The histological diagnosis of specimens obtained by biopsy was adenocarcinoma and transanal ultrasonography revealed the tumor localization within the submucosal layer in the rectum. Endoscopic mucosal resection (EMR) was performed. Histopathological examination established the diagnosis of carcinoid tumor in the rectum. Frequencies of the pedunculated type in rectal carcinoids were reported to be 2.4% to 7.1% in the literature. Because of its rarity, pedunculated configuration may confuse the endoscopic diagnosis of carcinoids. Treatment for carcinoids of 1 to 1.5 cm in size remains controversial. Although such tumors are technically respectable by EMR, careful attention must be paid in dealing with these tumors because there may be unexpected behaviors of the tumors.