Purpose: There is a controversy about the treatment of left-sided obstructive colorectal cancer. Recently, experience using an expandable metallic stent for relief of the obstruction has been increasing, but its oncological safety has not been confirmed. Therefore, we designed this study to evaluate the oncological safety of a metallic stent for the treatment of left-sided obstructive colorectal cancer. Methods: Forty-six patients with left-sided obstructive colorectal cancer who underwent a curative resection from 1994 to 2004, were retrospectively evaluated. Nineteen emergency operations (1994~2003) and 27 metallic stent insertions (2000~2004) were compared based on clinicopathologic features, postoperative complications, recurrence rates, and survival rates. Results: There were no significant differences in age, location, sex, and recurrence rate between the two groups. The complication rate in the emergency group was higher than it was in the stent group, but this difference was not statistically significant (26.3% vs. 14.8%; P=0.33). The overall and the disease-free survival rates were not significantly different. Conclusions: Because there was no significant differences in survival rate and recurrence rate between the two groups, metallic stent insertion can be used safely in the preoperative treatment of obstructive left-sided colorectal cancer.