Abstract Background Ulcerative colitis (UC) patients requiring colectomy often have a staged ileal pouch anal anastomosis (IPAA). There are no prospective data comparing timing of pouch creation. We aimed to compare 30-day adverse event rates for pouch creation at the time of colectomy (PTC) with delayed pouch creation (DPC). Methods Using prospectively collected data from 2011–2015 through the National Surgical Quality Improvement Program, we conducted a cohort study including subjects aged ≥18 years with a postoperative diagnosis of UC. We assessed 30-day postoperative rates of unplanned readmissions, reoperations, and major and minor adverse events (AEs), comparing the stage of the surgery where the pouch creation took place. Using a modified Poisson regression model, we estimated risk ratios (RRs) with 95% confidence intervals (CIs) adjusting for age, sex, race, body mass index, smoking status, diabetes, albumin, and comorbidities. Results Of 2390 IPAA procedures, 1571 were PTC and 819 were DPC. In the PTC group, 51% were on chronic immunosuppression preoperatively, compared with 15% in the DPC group (P < 0.01). After controlling for confounders, patients who had DPC were significantly less likely to have unplanned reoperations (RR, 0.42; 95% CI, 0.24–0.75), major AEs (RR, 0.72; 95% CI, 0.52–0.99), and minor AEs (RR, 0.48; 95% CI, 0.32–0.73) than PTC. Conclusions Patients undergoing delayed pouch creation were at lower risk for unplanned reoperations and major and minor adverse events compared with patients undergoing pouch creation at the time of colectomy.