The successful investigation and development of effective treatment programmes for any disorder is closely dependent on the development of reliable and valid assessment procedures. Anorexia nervosa would seem to be no exception in this respect. At present, while the diagnosis of anorexia nervosa seems fairly easy to establish, the assessment of severity, response to various treatment regimes, and prognosis pose rather more of a problem. Reliance on criteria such as weight status and gain, return of menstruation, psychosexual adjustment, etc., is inadequate, especially in the assessment of short-term effects of various therapeutic conditions. Recently Slade and Russell (1972) have described an objective technique for measuring ‘perception of body size‘, an area in which they found anorexia nervosa patients to be defective. Clearly, however, other reliable, objective assessment techniques are needed as well.