The patient is a 95-year-old male with underlying disease of hypertensive cardiovascular disease, Type 2 diabetes mellitus, and old cerebrovascular accident. Persistent abdominal cramping pain with fullness sensation and poor appetite had been noted. The flexible colonoscopy could not pass through sigmoid colon. Abdomen computed tomography demonstrated tumor obstruction over sigmoid colon, measurable size in 5.2 cm, with highly suspicion of duodenum invasion. During operation, tumor which located in the sigmoid colon invaded to fourth portion of the duodenum. En bloc resection of the tumor, duodenorrhaphy, and feeding jejunostomy were performed. An end-to-end anastomosis and protective loop ileostomy formation at the right lower quadrant were performed as totally bypass of anastomoses consequently. Direct invasion of colorectal adenocarcinoma into adjacent structures occurs frequently, but only rarely in the duodenum involved. In the case presented above, we could aim that active surgical management is useful for improving patient prognosis without increasing the risk associated with surgery.