PURPOSE: Although the cancer of the right side colon is usually managed by primary anastomosis following resection, but the optimal management of obstructing left side colon cancer is controversial. So, we performed this study to evaluate the feasibility and safety of subtotal or total colectomy as a method of one-stage operation in malignant obstruction of left side colon. METHODS: We analyzed retrospectively 35 patients with obstructing left side colon cancer among 74 cases of obstructing colorectal carcinoma who were treated surgically at the Wallace Memorial Baptist Hospital from January 1989 to December 1998. RESULTS: One-stage operation was performed in 16 patients (subtotal colectomy in 13, total colectomy in 3). Staged operation was performed in 15 patients (two-stage operation in 10, three-stage operation in 5). Palliative colostomy was performed in 4 patients. Postoperative complications had been developed in 6 patients (37.5%) with subtotal or total colectomy group and in 7 patients (46.7%) with staged operation group. The postoperative frequent bowel movement was shown in 13 patients (81.2%) with subtotal or total colectomy group and in 7 patients (70.0%) with staged operation group. Frequent bowel movement was improved with antidiarrheal medications within 3 months. Operative mortality was 6.3% (1 patient) in subtotal or total colectomy group and 13.3% (2 patients) in staged operation group. There was no significant difference in morbidity and mortality statistically between two groups. CONCLUSIONS: We believe that subtotal or total colectomy as a method of one-stage operation can be performed with acceptable morbidity and mortality in selected patients with obstructing left side colon cancer.