Surgery is the cornerstone of treatment of primary colorectal cancer, independent of the patients age and extent of disease. In the case of locoregionally confined tumors, an en-bloc resection of the primary tumor and adequate lymph node dissection should be performed. However, this is still not generally done. A subtle surgical technique is the most important prophylaxis against local recurrences. Standardized operative techniques, extended resections and perioperative measures led to a reduction of the rate of palliative resections and to a reduction of perioperative mortality (approximately 3%). However, despite modern surgical approaches, the long term prognosis of patients with stage II/III was not essentially improved. Therefore, especially in these stages, a further improvement of the current situation can at best expected by perioperative chemotherapy +/-irradiation.