Background Surgical resection of the diseased bowel in Crohn's disease is unfortunately not curative, and postoperative recurrence remains a problem in these patients. Aim To review the rates of and risk factors for clinical and endoscopic recurrence in population-based studies, referral centres and randomised controlled trials. Methods We searched MEDLINE (source PUBMED, 1966 to September, 2011). Results In randomised controlled trials, clinical recurrence in the first year after surgery occurred in 10-38% of patients, whereas endoscopic recurrence in the first year was reported in 35-85% of patients. In population-based studies, approximately half of patients experienced clinical recurrence at 10 years. In referral centres, 48-93% of the patients had endoscopic lesions (Rutgeerts' score >= 1) in the neoterminal ileum within 1 year after surgery, whereas 20 -37% had symptoms suggestive of clinical recurrence. Three years after surgery, the endoscopic postoperative recurrence rate increased to 85-100%, and symptomatic recurrence occurred in 34-86% of patients. Smoking is the strongest risk factor for postoperative recurrence, increasing by twofold, the risk of clinical recurrence. Prior intestinal resection, penetrating behaviour, perianal disease and extensive bowel disease (> 50 cm) are established risk factors for postoperative recurrence. Risk factors for postoperative recurrence remain poorly defined in population-based cohorts. Conclusion Endoscopic and clinical postoperative recurrence remains common in patients with Crohn's disease, and the identification of risk factors may allow targeted strategies to reduce this recurrence rate.