Objectives.The authors examine whether physician education has enduring effects on treatment of depression.Methods.Depressed primary care patients initiating antidepressant treatment from primary care clinics of a staff-model health maintenance organization were studied. Quasi-experimental and before-and-after comparisons of physician practices, supplemented with patient surveys, were used to compare the process of care and depression outcomes. Intervention consisted of extensive physician education that spanned a 12-month period. This included case-by-case consultations, didactics, academic detailing (eg, clearly stating the educational and behavioral objectives to individual physicians), and role-play of optimal treatment. Main outcome measures were divided into two groups. Quasi-experimental samples included: (1) antidepressant medication selection and (2) adequacy (dosage and duration) of pharmacotherapy. Survey samples included: (3) intensity of follow-up; (4) physician delivered educational messages regarding depression treatment; (5) patient satisfaction; and (6) depression outcomes.Results.No lasting educational effect was observed consistently in any of the outcomes measured.Conclusions.There was no enduring improvement in the treatment of depression for primary care patients. Depression treatment guidelines were achieved contemporaneously, however, for intervention patients enrolled in a multifaceted program of collaborative care during the training period. These results suggest that continuing programs of reorganized service delivery to support the role of a primary care physician (eg, on-site mental health personnel, close monitoring of patient progress and adherence), in addition to physician training, are essential for the success of guideline implementation.