Small-cell carcinoma of the rectum is an infrequent pathologic finding, and its precise incidence is unknown. Its incidence is less than 0.2 percent among all colorectal cancers. This tumor manifests highly aggressive behavior. The treatment of choice is combination chemotherapy similar to that used for small-cell carcinoma of the lung, but in small localized tumors surgery plus chemotherapy is an alternative. We present two cases of small-cell carcinoma of the lower rectum and a review of the literature.