An 86-year-old woman was diagnosed with ulcerative colitis (UC) in the 1970s. A colonoscopy performed 40 years thereafter revealed a 0-Is lesion in the upper rectum, and pathological examination showed well-differentiated adenocarcinoma. The lesion was diagnosed as colitic cancer based on the pathological findings and the 40-year interval since the diagnosis of total colitis type of UC. The patient was in good overall health with good anal function, based on the clinical examination and manometric study;she wished to undergo sphincter-preserving operation. Restorative proctocolectomy with ileal pouch-anal canal anastomosis that preserved the anal canal mucosa was performed. The postoperative course was good, with a defecation frequency of 4-5 times/day without fecal incontinence, and the patient resumed her preoperative lifestyle with very few alterations. Even in elderly patients aged >80 years who have UC, restorative proctocolectomy is feasible for those in good general health and with relatively good anal function, determined based on the daily defecation activity and anal manometry.