Angiosarcoma is a malignancy that occurs rarely in the gastrointestinal tract. We present a case of a 77-year-old male who had rectal bleeding and obstructive bowel symptoms. A large near-obstructing mass was seen endoscopically, but biopsies were inconclusive. A CT scan showed a large sigmoid lesion, and the patient had surgical resection. A large hemorrhagic-appearing tumor was found at operation. Angiosarcoma of the sigmoid colon was diagnosed on histologic examination. After colonic resection, the patient rapidly developed numerous liver metastases and died six months later. A review of the literature reveals only 12 other reported cases of colorectal angiosarcoma; 62 percent of these patients died within one year of surgical resection. The role of adjuvant radiation and/or chemotherapy is unclear. In conclusion, colorectal angiosarcomas are rare tumors that behave very aggressively, and the outcome is generally poor.