PURPOSE: The necessity of a protective stoma in patients undergoing low anterior resection with total mesorectal excision for primary rectal cancer is discussed controversially. We conducted a randomized, controlled, pilot-study to evaluate the need for diverting ileostomy in patients undergoing low anterior resection [NCT00457327]. METHODS: Forty patients after elective sphincter-saving low anterior resection were eligible for intraoperative randomization. The primary objective of this trial was to demonstrate similar risks after the resection with both techniques. A priori stopping rules were defined for early termination of the trial. RESULTS: Between July 4, 2006 and March 12, 2007, a total of 41 patients were screened and 34 patients were randomized. Eighteen patients were randomized to the stoma group and 16 patients to the nonstoma group The symptomatic anastomotic leakage rate was significantly higher in the nonstoma group (37.5 percent) than in the stoma group (5.5 percent, P = 0.02). In all six cases in the nonstoma group, reoperations were necessary. The study was stopped after 34 patients were included. A meta-analysis of the available data confirmed the value of a protective ostomy for patients undergoing low anterior resection. CONCLUSIONS: The data demonstrate a high risk for patients undergoing low anterior resection without diverting ileostomy.