A46 -year-old male presented with bloody stool and a descending colon tumor, as identified using colon fiberscopy. The patient did not complain of any remarkable abdominal symptoms. Computed tomography revealed descending colon tumor intussusception. We performed partial resection of the descending colon and D2 lymphadenectomy without intraoperative reduction. The descending colon was barely attached to the retroperitoneum and was mobile. The underlying tumor was type 1 and measured 8.3×5.8 cm. The pathology report indicated a mucinous adenocarcinoma with extension through the submucosa into the subserosa, and metastasis in 6 nearby lymph nodes(n2). Intussusception is relatively rare in adults, particularly in portions of the colon fixed to the retroperitoneum, such as the descending colon. In contrast to previous reports of descending colon intussusception caused by age-related tissue dysfunction, we report our experience with a young patient and present the results obtained.