Although the etiology of pouchitis after ileal pouch-anal anastomosis (IPAA) is unknown, its manifestations resemble those of nonspecific inflammatory bowel disease, including, anecdotally, the apparent ability to evoke extraintestinal manifestations (EIM) of inflammatory bowel disease (IBD). Our aim was to determine in what manner pouchitis and EIMs were associated. The computerized records of 819 consecutive patients who underwent IPAA between January 1981 and December 1988 were reviewed. Eighty-five patients were excluded (because of incomplete follow-up, death, or permanent ileostomy). Follow-up of the remaining 734 patients was complete (mean, 41 months). The mean age was 32 years and the ratio of men to women was 1:1. Ileal pouch-anal anastomosis was performed for chronic ulcerative colitis in 91% of patients and for familial adenomatous polyposis in 9%. Pouchitis occurred in 31% of chronic ulcerative colitis patients and 6% of familial adenomatous polyposis patients (p less than 0.01). The mean time to first occurrence was 17 months. Pouchitis recurred in 61% of patients at risk. Patients with preoperative and postoperative EIMs had significantly higher rates of pouchitis than did patients without EIMs (39% preoperative EIMs versus 26% with no EIMs, p less than 0.001; 53% postoperative EIMs versus 25% with no EIMs, p less than 0.001). Of patients with pouchitis in whom EIMs resolved after IPAA but then recurred (n = 12), EIMs recurred when pouchitis occurred and abated when pouchitis was treated in seven patients. We concluded that pouchitis occurred frequently after IPAA and that patients with EIMs were at higher risk of developing pouchitis than were patients who never had EIMs. Furthermore some patients experienced a temporal relationship between flares of EIMs and pouchitis. These results imply that pouchitis may be a novel manifestation of inflammatory bowel disease persisting after operation.