&NA;To establish whether patients with indeterminant colitis (patients with ulcerative colitis whose surgical specimens also show features of Crohn's colitis) have an adverse outcome after ileal pouch‐anal anastomosis (IPAA), the authors reviewed the pathologic reports and postoperative status of 514 consecutive patients who underwent IPAA for chronic ulcerative colitis (CUC). Twenty‐five patients (5 percent) had features of indeterminant colitis (IC), including unusual distribution of inflammation, deep linear ulcers, neural proliferation, transmural inflammation, fissures, creeping fat, and retention of gobletcell population. The clinical and functional outcome of these 25 IC patients was compared with that of the remaining 489 CUC patients. The mean follow‐up was 38±18 months. No significant differences in complication rates, pouch function, incidence of “pouchitis,” or requirement for pouch excision were detected in the two groups at follow‐up. Although the authors are continuing to perform IPAA on patients with IC, a better definition of the IC patient and a more objective, prospective analysis of outcome of IC following IPAA is required before confident and specific treatment policies can be recommended.