We report two cases of neuroendocrine carcinoma of the rectum. CASE 1: A 50s woman was diagnosed as rectal cancer and underwent anterior resection of the rectum and lymphnode dissection. The histological diagnosis was neuroendocrine carcinoma with peritoneal dissemination. She was treated with chemotherapy as an outpatient. One year later from the operation, multiple liver metastases were revealed and she died eight months later. CASE 2: A 50s man underwent endoscopic mucosal resection (EMR) of the rectum as rectal tumor and histological diagnosis was an early well-moderate deferenciated carcinoma and its cut-tend was unclear. He received a careful follow-up. One year later, a follow-up colonoscopy revealed a submucosal tumor in the lower rectum. He was diagnosised with local reccurence of rectal cancer, and then underwent an abdominoperineal resection of the rectum and lymphnode dissection. The histological diagnosis was poorly differenciated neuroendocrine carcinoma with lymphnode metastasis. Two months later from the operation, a local reccurence was revealed and he was treated with octreotide and irradiation.