• The National Institute of Mental Health (NIMH) Treatment of Depression Collaborative Research Program (TDCRP) is the first multisite coordinated study initiated by the NIMH in the field of psychotherapy research. Three research sites, using an identical research protocol, are investigating the effectiveness of two forms of brief psychotherapy (cognitive behavior therapy and interpersonal psychotherapy) in the treatment of outpatient depression. Three training sites have trained experienced therapists in a standard fashion for each of the psychotherapies and the comparison pharmacotherapy conditions. This report presents the background of the TDCRP, the rationale for the choice of patient population and treatment conditions, and the research plan for both the training/pilot phase and the outcome study currently in progress, and discusses the potential contributions of the program to the field of psychotherapy research.