PURPOSE: In terms of functional outcome, there is evidence of the superiority of the colonic J-pouch over a straight coloanal anastomosis. Even though the colonic J-pouch was created to restore a neorectal reservoir, manometric data show that the volume of a short colonic J-pouch does not differ from a straight coloanal anastomosis. We speculate that the advantage of the colonic J-pouch is not in creating a larger neorectal reservoir, but rather related to decreased motility. Maurer and Z’graggen recently described a new colonic pouch design, performing a “transverse coloplasty” pouch. The purpose of this pilot study was to compare the feasibility and functional outcome of the 5-cm colonic J-pouch vs. the coloplasty pouch. METHODS: From February 2000 to June 2001, we randomized 40 consecutive patients with distal rectal cancer (<12 cm from the anal verge) into the J-pouch or coloplasty group. A low rectal resection and coloanal anastomosis was performed in all patients. Functional data were collected by a standardized questionnaire and anorectal manometry, preoperatively and six months postoperatively. Primary end points of the study were potentially differences of both groups regarding technical feasibility, stool frequency, and anorectal manometry. RESULTS: The construction of a coloplasty pouch was feasible in all cases of the coloplasty group, but not in 5 of 20 (25 percent) patients of the J-pouch group, because of colonic adipose tissue. Six months after operation or stoma closure, respectively, stool frequency was 2.75 ± 1 per day in the J-pouch group and 2 ± 2 per day in the coloplasty group. There was no significant difference in resting and squeeze pressure and neorectal volume between both groups, but an increased neorectal sensitivity in the coloplasty group. CONCLUSION: We found similar functional results in the coloplasty group compared to the J-pouch group. The neorectal sensitivity was increased in the coloplasty group. Therefore, the colonic coloplasty seems to be an attractive pouch design because of its feasibility, simplicity, and effectiveness.