Emergency management of obstructing colonic cancer depends on both tumor location and stage, general condition of the patient and surgeon’s experience. Right sided or transverse colon obstructing cancers are usually treated by right hemicolectomy–extended if necessary to the transverse colon–with primary anastomosis. For left-sided obstructing cancer, in patients with low surgical risk, primary resection and anastomosis associated with on-table irrigation or manual decompression can be performed. It prevents the confection of a loop colostomy but presents the risk of anastomotic leakage. Subtotal or total colectomy allows the surgeon to encompass distended and fecal-loaded colon, and to perform one-stage resection and anastomosis. Its disadvantage is an increased daily frequency of stools. It must be performed only in cases of diastatic colon perforation or synchronous right colonic cancer. In patients with high surgical risk, Hartmann procedure must be preferred. It allows the treatment of both obstruction and cancer, and prevents anastomotic leakage but needs a second operation to reverse the colostomy. Colonic stenting is clinically successful in up to 90% in specialized groups. It is used as palliation in patients with disseminated disease or bridge to surgery in the others. If stent insertion is not possible, loop colostomy is still indicated in patients at high surgical risk.