Objective: To describe changes in physical activity (PA) and exercise dependence score during treatment of eating disorders (ED), and to explore correlations among changes in PA, exercise motivation, exercise dependence score and ED psychopathology in excessive and nonexcessive exercisers.Method: Thirty-eight adult females receiving inpatient treatment for anorexia nervosa, bulimia nervosa or ED not otherwise specified participated in this prospective study. Assessments included accelerometer assessed PA, Exercise Dependence Scale, Reasons for Exercise Inventory, ED Examination, and ED Inventory.Results: Amount of PA was significantly reduced in non-excessive exercisers during treatment, in excessive exercisers there was a trend towards reduced amount of PA from admission to discharge. In excessive exercisers, reduced ED psychopathology was correlated with reduction in exercise dependence score and perceived importance of exercise to regulate negative affects, but not with importance of exercise for weight/ appearance. These associations were not found in non-excessive exercisers.Discussion: Excessive exercise is an important issue in longstanding ED, and the excessive exercising patients need help to develop alternative strategies to regulate negative affects. V