The objective was to evaluate the clinical value of preventative ileostomy following ultralow anterior rectal resection in decreasing the incidence of anastomotic leakage. For this purpose, 62 cases that had undergone ultralow anterior rectal resection during the period from June 2007 to June 2008 were included in this study. Preventative ileostomy was performed in 36 cases (group A) and 26 cases with no preventative ileostomy performed were included as controls (group B). The incidence rate of anastomotic leakage in both groups was compared. The results show that five cases in group A reported anastomotic leakage while no anastomotic leakage was reported in group B. Therefore, it was concluded that preventative ileostomy could effectively decrease the incidence of anastomotic leakage.