Since 1980, restorative proctocolectomy has been established for surgical therapy to ulcerative colitis. The crucial points of this procedure are mucosectomy of the anorectal mucosa and pouch anal anastomosis. Mucosectomy is often difficult due to long standing acute and chronic inflammation and incomplete microscopically and leakage of pouch anal anastomosis is relatively high probably due to steroid given prior to surgery or direct effect of anorectal mucosal inflammation. Regards to postoperative bowel function, nocternal soiling is frequently recognized in the patients who received this operation. To overcome these technical and functional disadvantages, anal transitional zone preservation without mucosectomy and stapled anastomosis between pouch and the upper rim of the puborectalis muscle has been performed. Our series of 84 cases with this modified method, anastomotic leakage was significantly decreased and nocternal soiling was completely disappeared within 7 months postoperatively. And one stage procedure became possible unless severe, or high doses of steroid given prior to surgery. Only one case of mild dysplasia was experienced in the remaining rectal mucosa which was disappeared at the next examination. Medical treatment to the remaining lesion was not necessary in the most of cases. Anal canal preservation is superior to mucosectomy in the points of bowel function and minimizing postoperative complications.