Neuroendocrine carcinoma of the colon is a very rare entity. However, this type of tumor is known to have aggressive progression and poor prognosis. A case of a 72-year-old male is presented in this report. A 3 cm sized tumor was found on the rectum with multiple liver metastases. The pathological findings including a positive immunohistochemical staining for synaptophysin and cytokeratin done with colonoscopic biopsy and liver biopsy confirmed the tumor as a neuroendocrine carcinoma. The nomenclature and definition of this disease still remains somewhat unclear, and not a small population of this disease may thus have been misdiagnosed and treated as other less aggressive entities, such as carcinoid tumor. The necessity to make an accurate differential diagnosis in such cases is thus emphasized because of different treatments and clinical courses. For its rarity and clinical significance, we report this case with a review of the literatures. (Korean J Gastrointest Endosc 2003;27:239-243)