Case-based discussion has been a key element of the assessment programme for psychiatrists in training under the guidance of the Royal College of Psychiatrists since 2007. Its incorporation within systems for recertification and thus revalidation for psychiatrists in established practice has now been piloted. This article discusses the origins of the instrument in Canada and the USA before describing its use in the UK. Case-based discussion is placed within the context of contemporary postgraduate medical education and the curricula of the College, offering practical guidance on how best to use this method for the assessment of reasoning and judgement. Finally, some questions are posed regarding the potential use of case-based discussion in the proposals for revalidation.