A 76-year-old man presented to the emergency room with abdominal pain and fatigue. The patient had a history of gastrointestinal bleeding. An abdominal computed tomographic scan showed collections of free air in the abdomen with obstruction of the distal small intestine and multiple masses in the liver. Laparotomy revealed a widespread malignant neoplasm in the abdomen, with multiple tumor nodules in the ileal wall, mesentery, and liver. The ileal wall was perforated within the area of one of the tumors. Pathologic examination of the lesion showed a neoplasm composed of solid sheets of spindle and undifferentiated cells, forming interlacing delicate vascular channels with atypical endothelial cells. The tumor cells were positive for the endothelial marker CD31, whereas reactivity for a broad panel of epithelial and other endothelial markers was negative. This case demonstrates that although angiosarcomas of the gastrointestinal tract are rare, they should be considered in cases of intestinal perforation or severe bleeding, especially in the elderly. A broad panel of immunochemical markers might be necessary to establish the pathologic diagnosis.