PURPOSE: As the oncologic safety of coloanal anastomosis (CAA) has been proven by many other authors, the incidence of CAA following a ultra-low anterior resection has increased. The purpose of this study is to evaluate the functional outcomes and complications for patients who underwent an ultra-low anterior resection and CAA for distal rectal cancer. METHODS: 57 patients underwent CAA following an ultra-low anterior resection between July 1997 and November 2003. 44 patients, who were followed up for more than 6 month after diverting ileostomy repair were evaluated for recurrence pattern, complications, and functional outcomes. RESULTS: The median follow-up period was 32.0+/-22.8 (8~83) months. The mean age of the patients was 54.3+/-10.4 (23~74) years. The types of anastomosis were straight CAA (n=20) and J pouch CAA (n=37). The mean tumor size was 4.1+/-1.9 (2~8) cm, the mean distal resection margin was 1.3+/-0.9 (0.2~4) cm. Six months later, the anastomosis distance following diverting ileostomy repair was measured at 3.24+/-0.6 (2~4) cm from the anal verge. The complications were multiple fistulas (n=3), fistula with anal stenosis (n=1), local recurrence with anal stenosis (n=1), anal stenosis (n=7). Anal incontinence (Kirwan grade III) was noted in 14 patients, and bowel movements more than 6 times per day were observed in 16 patients. Overall recurrence occurred in 6 patients (13.6%). The 5-years survival rate was 84.4%, and the 5-year disease-free survival was 68.9%. CONCLUSIONS: Although CAA in patients with rectal cancer provides excellent long-term survival, a low risk of recurrence, in tolerable function, complications, and poor functional outcomes have been observed with CAA; therefore, the choice of this method should be considered carefully.