Of 518 patients undergoing the ileal pouch-anal anastomosis (IPAA), 17 (13 with chronic ulcerative colitis [CUC] and four with familial polyposis coli [FPC] ) also had a total of 22 cancers of the colorectum. Tumors were concentrated distally (rectum 6; sigmoid colon 5; proximal colon 11) and were diagnosed preoperatively in eight patients. Histologic grade and stage were as follows: grade I, 36 percent; II, 23 percent; III, 23 percent; IV, 18 percent; stage A, 5 percent; B1, 32 percent; B2, 18 percent; C1 and C2, 45 percent. Median hospital stay was 17 days with no operative mortality. Relaparotomy was required in 35 percent (sepsis in four patients; obstruction in two) and minor procedures were done in 12 percent (anastomotic dilatation in one; rectovaginal fistula in one). Mean frequency of defecation was 6.4/day, 1.0/night; incidence of minor seepage, 17 percent (day), 50 percent night); incidence of pouchitis, 8 percent; intermittent dyspareunia, 17 percent of six women. One patient died from hepatic metastases nine months after operation. IPAA should be considered in favorable cancers complicating CUC or FPC, although it may be contraindicated in advanced rectal cancer, and may be unsuitable in advanced proximal cancer.