Background: Understanding motivation to change is a key issue in both the assessment and the treatment of eating disorders.Therefore,sound instruments assessing this construct are of great help to clinicians.Accordingly,the present study analysed the psychometric properties of the Anorexia Nervosa Stages of Change Questionnaire (ANSOCQ),including its relation to coping style and self-esteem. Methods: N = 92 adolescents referred to an eating disorders outpatient clinic meeting criteria for anorexia nervosa gave written informed consent to participate in this study and completed the ANSOCQ,the Eating Disorder Inventory,the Eating Attitudes Test,the Body Image Questionnaire,two questionnaires measuring Self-Related Cognitions and the Coping Across Situations Questionnaire.After a treatment period of nine months,clinical anorexia nervosa diagnosis and the body mass index were re-assessed.In addition to exploratory factor analysis,correlational analysis was used to test for the convergent validity of the ANSOCQ and logistic regression analysis was used to test its predictive validity. Results: The ANSOCQ had good psychometric properties.Factor analysis yielded two meaningful factors labelled as ' weight gain and control ' and ' attitudes and feelings '.Internal consistencies of the two factors amounted toCronbach ' s alpha =.87 and.76, respectively.Significant correlations with other scales measuring eating disorder psychopathology were indicative of meaningful construct validity.Higher motivation to change was related to higher self-esteem and a more active coping style.Higher (positive) ANSOCQ total scores predicted remission of anorexia nervosa after nine months of treatment.A higher score on ' attitudes and feelings ' was a protective factor against drop-out from intervention. Conclusions: The ANSOCQ is a clinically useful instrument for measuring motivation to change in adolescents with AN.Two factorial dimensions explain most of the variation.Self-esteem and coping style are relevant additional constructs for the understanding of the motivation to change in anorexia nervosa.