BACKGROUND: Elderly patients with inflammatory bowel disease [IBD] are fragile in many respects. Therefore, in these patients, we studied postoperative complications [new abdominal surgery and serious infections after the first IBD surgery]. METHODS: This is a nationwide cohort study based on Danish health registries and included patients with IBD undergoing surgery. The study population was split into ulcerative colitis [UC] and Crohn's disease [CD]. The exposed cohort [elderly] constituted those at an age of >/=60 years at first IBD surgery, and the unexposed [adults] those with surgery at the age of 18-59 years. We estimated adjusted hazard ratios [aHRs] of: a] new abdominal surgery within 2 years; and b] serious [hospital-diagnosed] infections within 6 and 12 months. We adjusted for several confounders including type of index surgery [laparoscopic or open]. RESULTS: The aHR for a new surgery among elderly with UC and CD were 0.69 [95% CI 0.58-0.83] and 0.98 [95% CI 0.83-1.15], respectively. In elderly with UC, the aHRs of infections within 6 and 12 months after surgery were 1.07 [95% CI 0.81-1.40] and 0.85 [95% CI 0.67-1.08], respectively. In the elderly with CD, the aHRs of infections within 6 and 12 months were 1.45 [95% CI 1.12-1.88] and 1.26 [95% CI 1.00-1.59], respectively. CONCLUSION: The elderly with IBD did not have an increased risk of new abdominal surgery within 2 years of the first surgery. Elderly with CD, but not UC, had an increased risk of serious infections within 6 months of surgery.