Background: The omentum has variable functions in surgical procedures. Nevertheless, there is very little information about the effect of omentum on abdominal complications after gastrectomy. The purpose of the present study was to determine the outcome of omentum-preserving gastrectomy for early gastric cancer. Methods: We evaluated 1,116 patients who had a gastrectomy for early gastric cancer between the years 2004 and 2006; 992 patients underwent conventional gastrectomy (CG), and 124 patients had an omentum-preserving gastrectomy (OPG). These cases were analyzed retrospectively. The early and late abdominal complications were compared between the CG and OPG groups. Results: The results of the study show no significant differences between the early abdominal complications in the CG and OPG groups. However, the late abdominal complication rate in the OPG was significantly lower than the CG (p = 0.026). The most common risk factor associated with early abdominal complications was type of operation. The combination of CG and early abdominal complication represented a statistically significant risk for late abdominal complications (p = 0.026, 0.031 respectively). Conclusion: The findings of this study demonstrate that the omentum-preserving gastrectomy in the treatment of early gastric cancer showed a lower rate of abdominal complications compared to the conventional gastrectomy.