SummaryThe aim of this paper is to review and critically evaluate the Clinical Assessment of Skills and Competencies (CASC) examination, introduced in June 2008. the history of clinical membership examinations and rationale for the new examination are considered. the development and implementation of the examination is described by means of a four-step model of assessment. Finally, the paper critically evaluates the assessment with reference to validity, reliability, practicability and effect on learner.