These guidelines have been commissioned by the Clinical Services and Standards Committee of the British Society of Gastroenterology (BSG) for clinicians and allied professionals caring for patients with inflammatory bowel disease in the United Kingdom. The authors of these guidelines were members of the BSG IBD Committee at the time. This committee is elected by fellow members of the IBD section of the Society. They replace the guidelines published in 2004 by Carter et al. They have been written with close reference to the recent European evidence-based consensus documents on Crohn’s disease and ulcerative colitis produced by the European Crohn’s and Colitis Organisation (ECCO) (https://www.ecco-ibd.eu/index.php (accessed Oct 2010)). Although these consensus documents provide a comprehensive and authoritative review of the evidence base underlying definitions, diagnosis and current management we believe there are still compelling reasons to issue a set of up-to-date guidelines for UK practice.