AIM: There is some evidence of functional superiority of colonic J-pouch over straight coloanal anastomosis (CAA)in ultralow anterior resection (ULAR) or intersphincteric resection. On the assumption that colonic J-pouch anal anastomosis is superior to straight CAA in ULAR with upper sphincter excision (USE: excision of the upper part of the internal sphincter) for low-lying rectal cancer, we compare functional outcome of colonic J-pouch vs the straight CAA.METHODS: Fifty patients of one hundred and thirty-three rectal cancer patients in whom lower margin of the tumors were located between 3 and 5 cm from the anal verge received ULAR including USE from September 1998 to January 2002. Patients were randomized for reconstruction using either a straight (n = 26) or a colonic J-pouch anastomosis (n = 24) with a temporary diverting-loop ileostomy. All patients were followed-up prospectively by a standardized questionnaire [Fecal Inco-ntinence Severity Index (FISI) scores and Fecal Incontinence Quality of Life (FIQL) scales].RESULTS: We found that, compared to straight anastomosis patients, the frequency of defecation was significantly lower in J-pouch anastomosis patients for 10 mo afterileostomy takedown. The FISI scores and FIQL scales were significantly better in J-pouch patients than in straight patients at both 3 and 12 mo after ileostomy takedown.Furthermore, we found that FISI scores highly correlated with FIQL scales.CONCLUSION: This study indicates that colonic J-pouch anal anastomosis decreases the severity of fecal incontinence and improves the quality of life for 10 mo after ileostomy takedown in patients undergoing ULAR with USE forlow-lying rectal cancer.