A one-stage operation for obstructing left-sided colorectal carcinoma remains controversial. This study was performed to compare our surgical management of patients with left-sided colorectal cancer (at or distal to splenic flexure) obstruction presenting to the Kaohsiung Medical University Hospital from January 1995 to December 2000. Ninety-six patients underwent immediate operation within 24 hours of admission. Of these, 73 patients (76%) who underwent immediate tumor resection and anastomosis in one stage after appropriate resuscitation were enrolled into our study. In one-stage operation subtotal coloectomy with ileocolic or ileorectal anastomosis (group 1) was performed in 46 patients (63%), and intraoperative bowel preparation followed by immediate resection (group 2) was undertaken in 27 patients (37%). In comparing the two groups, there was no significant difference in the postoperative mortality (8.7% in group 1 vs. 7.4% in group 2) or cumulative 5-year survival rate (36.7% in group 1 vs. 35.7% in group 2) (all p > 0.05). However, mean operation time (178 +/- 12 min in group 1 vs. 238 +/- 12 min in group 2) and postoperative wound infection rate were significantly lower (10.9% in group 1 vs. 29.6% in group 2). The incidence of postoperative diarrhea was more prominent in the group 1 than group 2 (32.6% in group 1 vs. 11.1% in group 2) (all p < 0.05). The results of our current study showed that primary resection and anastomosis by subtotal colectomy is an acceptable means for the treatment of patients with obstructing left-sided colorectal carcinomas when the patient's condition is feasible.