Postoperative recurrence of Crohn's disease is often inevitable. Certain risk factors such as smoking, young age, and a perforating disease behavior have been identified. Patients running an enhanced risk should be treated with mesalamine or, with higher success rates, with azathioprine. An endoscopic evaluation of the neoterminal ileum 6 to 12 months after surgery provides relevant information predicting the further clinical course and can be used as a guide to adjust medical therapy.