The aim of the present prospective-naturalistic study was the evaluation of psychosomatic inpatient treatment for anorexia nervosa (AN) and bulimia nervosa (BN). 128 patients with eating disorders (n=59 AN and n=69 BN) were investigated on admission and discharge using the following standardized questionnaires: eating disorder symptoms (EDI), general psychopathology (BSI), quality of life (SF-12), and personal resources (SOC-13, SWE). Moderate to large effect sizes were achieved for the eating disorder symptoms; in addition, general psychopathology was substantially reduced at the end of treatment, and quality of life as well as personal resources were enhanced. Personal resources were found to be the strongest predictors for therapy outcome. Based on our data, important insights and recommendations may be gained for the inpatient treatment of eating disorders, especially with regard to the potential influence of personal resources.