The paper gives an overview of the 4 randomized-controlled multi-center psychotherapy studies and the associated studies of the Eating Disorders Diagnostic and Treatment Network (EDNET). The multi-center trials include an outpatient treatment trial for AN comparing focal psychodynamic psychotherapy, cognitive-behavioral therapy, and treatment as usual, a trial comparing in- and day-patient treatment in adolescents with AN, and two internet-based relapse prevention trials for patients with AN and with BN after discharge from inpatient treatment. Associated studies are grouped around these core proposals covering neuropsychology, structural as well as functional neuroimaging, genetics, endocrinology, and moderators and mediators of treatment outcome.