In UICC stage I a selected group of patients with T1 tumours and a low risk profile regarding simultaneous lymph node metastases can be treated by endoscopic resection alone, if the tumour is thereby completely removed. In UICC stage II an adjuvant chemotherapy (CT) should not be routinely performed. However, in high risk UICC stage II patients (T4 tumour, less than 12 examined lymph nodes, emergency surgery, intraoperative tumour perforation), an adjuvant CT with infusional 5-FU/FA should be recommended. The state of the art in UICC stage III is an adjuvant CT with FOLFOX. In this tumour stage no beneficial effect of CT involving irinotecan or monoclonal antibodies has been documented. Due to CT-induced side effects an infusional 5-FU/FA protocol or oral capecitabine should be given in patients older than 70 years. In stage UICC IV with resectable liver metastases, surgical resection of the primary tumour and the metastases should be implemented. Since no conclusive data are currently available regarding the beneficial effect of neoadjuvant, perioperative or adjuvant CT in this setting, the therapeutic strategy should be individually discussed between surgeons and oncologists (tumour board). In cases of non-resectable liver metastases a neoadjuvant CT should be performed, preferentially with a FOLFOX protocol in combination with targeted therapies, i.e., the monoclonal antibody cetuximab, aimed at tumour regression with radical metastasectomy as the secondary intent (R0). Patients with UICC stage II colon cancer and microsatellite instability (MSI) apparently experience a better prognosis but do not profit from an adjuvant CT with 5-FU/FA alone. If a CT is under consideration for these patients, the MSI status should be determined on tumour tissue. In cases of a positive result a combination CT, i.e., with FOLFOX, should be given. The relevance of the MSI status in other tumour stages is as yet unknown. Before targeted therapies, i.e., cetuximab or panitumumab, are initiated, the KRAS status needs to be determined, since therapies with antibodies against the epithelial growth factor receptor (EGFR) are only effective in tumours bearing the KRAS wild-type.