Ileocolonoscopy remains the gold standard in diagnosing postoperative recurrence. After excluding stricture, wireless capsule endoscopy seemed accurate in small series, but no validated score is available. Ultrasonography is a non-invasive diagnostic method reducing radiation exposure and emerging as an alternative tool for identifying post-operative recurrence. Computed tomography enteroclysis yields objective morphologic criteria that help differentiate between recurrent disease and fibrostenosis at the anastomotic site, but ionising radiation exposure limits its use. Magnetic resonance imaging may be as powerful as ileocolonoscopy in diagnosing postoperative recurrence and in predicting the clinical outcome using specific MR-scores. Biomarkers such as faecal calprotectin and faecal lactoferrin showed promising results, but their specificity in the postoperative period will require further investigation. Numerous medications have been tested to prevent and/or to treat postoperative recurrence. Efficacy of mesalamine is very low and comparable to placebo in most series. Thiopurines have modest efficacy in the postoperative setting and are associated with a high rate of adverse events leading to drug withdrawal. Antibiotics such as metronidazole or ornidazole may be effective, but toxicity and drug resistance prevent their long-term use. Anti-Tumour Necrosis Factor therapy is the most potent drug class to prevent and to treat postoperative recurrence in Crohn's disease.