Several studies have compared loop ileostomy with loop colostomy to defunction colorectal anastomoses. The discordant results may be due to the heterogeneity of the indications. We therefore performed a retrospective study to compare the two procedures in a homogeneous group of patients operated on electively for rectal cancer. Among 462 consecutive patients undergoing rectal resection for cancer during 1986–1998, 60 had a loop colostomy and 107 a loop ileostomy to defunction a low anastomosis. The two groups were similar with respect to age, gender, obesity, tumor stage, and duration before closure (109 vs. 104 days; p= 0.28). All the stoma-related complications that occurred after construction and after closure of the stoma were recorded. There were no stoma-related deaths in the two groups. After stoma construction, the morbidity rate was significantly higher following loop colostomy than after loop ileostomy (35% vs. 19%; p= 0.02). After stoma closure the complication rate was significantly higher in the colostomy group than in the ileostomy group (34% vs. 12%; p= 0.004). The risk of surgical reintervention related to the morbidity of both construction and closure of the stoma was twice as high after loop colostomy than after loop ileostomy (22% vs. 9%; p= 0.03). The results of this study showed that, in our experience, the overall stoma-related morbidity and risk of reoperation were significantly lower after loop ileostomy than after loop colostomy. This suggests that loop ileostomy is the best procedure for defunctioning colorectal anastomoses electively. We therefore recommend using a loop ileostomy during rectal cancer surgery.