Purpose: We sought to describe the incidence of and factors associated with post-colectomy complications among UC pts in Olmsted County, Minnesota. Methods: We identified all pts who had undergone ≥1 surgery for UC in a cohort diagnosed with UC between 1970–2001. Colectomies were classified as: total proctocolectomy (TPC) with ileal pouch-anal anastomosis (IPAA), subtotal colectomy (SC) with ileostomy, TPC with ileostomy, and partial colectomy (PC). We examined post-colectomy complications by colectomy type. The association between colectomy type and time to first complication was assessed with proportional hazards regression analysis. Results: A total of 47/316 UC pts (14.8%) underwent colectomy during the follow-up (f/u) period. The colectomy distribution was: TPC-IPAA 60%, SC-ileostomy 5%, TPC-ileostomy 33%, and PC 2%. Within the first 2 yrs of f/u, a variety of complications were observed, including (rate/1,000 pt-yrs): wound infection (204.9), anastomotic leak (56.9), fistula (22.8), abscess (68.3), small bowel obstruction (148.0), anastomotic stricture (56.9), ileus (11.4), pouchitis (148.0), and stomal problems (45.5). During the same period, the crude rate of infective and non-infective complications was 296 and 512 per 1000 pt-yrs, respectively. The total crude rate was 808/1000 pt-yrs. See table for cumulative risk of any complication following colectomy. Regression analysis indicated that, relative to TPC-ileostomy, IPAA patients had a 1.7 times greater risk of experiencing an infective complication (95% CI, 0.5–6.3) and a 2.4 times greater risk of experiencing a non-infective complication (95% CI, 0.98–6.1), but only the latter was of borderline significance. Conclusion: In this population-based study of UC pts undergoing colectomy, a number of post-surgical complications were observed, for a crude rate of over 800 per 1,000 pt-yrs of f/u in the first 2 yrs, and a cumulative risk of 68.0% at 5 yrs. There was a borderline significant association between IPAA and time to first non-infective complication.