Imposture syndrome is widespread among physicians and medical students. It is defined as a psychological experience in which people doubt their own skills and achievements despite proven successes and thus have an unfounded fear of being found out. This can have serious consequences, such as anxiety and/or depressive disorders, and can lead to burn-out. The Clance scale is a self-assessment tool used to measure the level of imposture experienced and, when appropriate, to assess the suffering caused. The aim of this article is to help recognise this syndrome, which is one way of preventing it.