Describes a two-day open examination, one of the assessment techniques used since 1980 for students on the Three Year Postgraduate Diploma Course in Textile Conservation, run by the Textile Conservation Centre in conjunction with the Courtauld Institute of Art, London. A brief description of the history and content of the diploma course precedes a detailed description of the open examination. Each student has two days to inspect a historic textile requiring conservation treatment and to prepare a detailed written report, which is the basis for a subsequent viva voce examination. The effectiveness of the open examination as an assessment technique is considered.