A day hospital group treatment program is detailed which could offer effective treatment to many patients with anorexia nervosa and bulimia nervosa who would otherwise require inpatient treatment. Important clinical advantages over an inpatient program are described. The psychotherapy is cognitive-behavioral oriented and is done in groups. A multi-disciplinary team approach is used. The day hospital treatment program includes psychological, social and eating-related interventions. Main characteristics are the motivation-phase, the contact between patients of different therapy-phases, the involvement of families in therapy and the support of self-help. First empirical outcome results are presented.