The aims of this study were to investigate the prevalence of anorexia nervosa, bulimia nervosa and partial syndromes in women general practice attenders to establish the relative proportions of 'conspicuous' and 'hidden' morbidity. A consecutive series of 540 women patients aged 16-35 years attending their family doctor were screened using a specially devised questionnaire, the weight and dietary practices survey. A total of 115 patients were selected for further assessment and of these 101 patients were interviewed using a standardized diagnostic interview for DSM III-R eating disorders. The prevalence of anorexia nervosa was 0.2% (one case), of bulimia nervosa 1.5% (eight cases) and of partial syndrome bulimia nervosa 5.4% (29 cases). Half of the cases of bulimia nervosa had not been identified by the general practitioner and two of these patients had been referred to specialists for treatment of secondary complications of the eating disorder. Hidden cases of bulimia nervosa or partial syndromes are relatively common in general practice. Certain key questions could be used by general practitioners in order to identify women with eating disorders.