Neuroendocrine carcinomas of the colon and rectum are rare and have been known as either carcinoid tumors or undifferentiated cancers in the past. This type of tumor frequently occurred at cecum and is known for its aggressiveness and poor prognosis, differing from ade nocarcinoma of colon. There has been no literature which describes endoscopic findings of colonic neuroendocrine carcinoma. Therefore, we report a case of neuroendocrine carcinoma of cecum in 36-year-old man with endoscopic findings. After right hemicolectomy followed by adjuvant chemotherapy, we have followed up the patient for 6 months without the evidence of recurrence. (Korean J Gastrointest Endosc 2004;28:102106)