Background: A SEMS (Self Expandable Metallic Stents) has been widely used for obstructive colorectal cancer as a bridge to surgery to avoid emergency surgery. However, it may increase the tumor spillage so that the long-term survival would be compromised. The aim of our study was to compare the short- and long-term outcome of surgery after stent insertion with those of emergency surgery alone for the left colon malignant obstruction patients. Methods: The medical records of patients who received curative resection due to obstructive primary left colon cancer and diagnosed to stage II or III from January 2004 to December 2010 in six hospitals affiliated to the Catholic Medical Center. Overall survival and disease free survival were compared between the SEMS (n = 158) and emergency surgery (n = 56) group. Short-term outcome was also compared. Factors affecting disease-free survival in the SEMS group were analyzed using the cox proportional hazards model. Results: Baseline characteristics were comparable between two groups by pathologic stage. Intra-operative complication (0.0% vs. 7.1%, p = 0.004), re-operation (1.3% vs. 7.1%, p = 0.042), post-operative hospital stay (11.2 ± 6.5 days vs. 14.6 ± 8.9 days, p = 0.010) and conversion rate (3.5% vs. 16.7%, p = 0.028) showed short-term advantages of the SEMS. 5-year DFS in stage II patients was 87.2% for the SMES group, 73.5% for the ES group (p = 0.117). Among stage III patients, 5-year DFS was 55.8% for the SEMS group and 72.0% for the ES group (p = 0.129). 5-year OS of the SEMS group was 90.2%, and of the ES group was 92.4% in stage II patients (p = 0.694). 5-year OS in the SEMS group was 82.8%, and the ES group 73.0% in stage III patients (p = 0.577). For the stage III SEMS patients, hospital of procedure (p = 0.041) and operation date (HR 0.400, 95% C.I 0.176-0.905, p = 0.028) were independent factors on disease free survival. Conclusions: If there’s an intervention team with sufficient experience for the SEMS and a sufficient preparation for emergency surgery, the SEMS is a good therapeutic option for malignant obstruction in left colon cancer.