The treatment of choice for left sided colonic obstruction is still controversial. We tried primary resection and anastomosis with the aid of intraoperative irrigation of the dilated proximal colon. Twenty-one cases of obstructive carcinoma of the left colon and four cases of sigmoid colon volvulus were managed using this approach. After the antegrade or retrograde intraoperative irrigation, primary resection and anastomosis without colostomy was performed in all 25 cases. There was only one case with anastomotic leakage. The satisfactory results of our present study and of the previous reports of intraoperative irrigation lead us to recommend intraoperative irrigation and primary anastomosis for left sided colonic obstruction except when the general condition of a patient is very poor or when the prognosis is expected to be poor due to the advanced spread of carcinoma.