The objective of this study was to test the effectiveness of two programs to improve the treatment of acute depression in primary care. Patients were randomly assigned to continued usual care or one of two interventions: feedback only and feedback plus care management. Feedback only comprised feedback and algorithm based recommendations to doctors on the basis of data from computerized records of pharmacy and visits. Feedback plus care management included systematic follow up by telephone, sophisticated treatment recommendations, and practice support by a care manager. Compared with usual care, feedback only had no significant effect on treatment received or patient outcomes. Patients receiving feedback plus care management had a higher probability of both receiving at least moderate doses of antidepressants (odds ratio 1.99, 95 percent confidence interval 1.23 to 3.22) and a 50 percent improvement in depression scores on the symptom checklist (2.22, 1.31 to 3.75), lower mean depression scores on the symptom checklist at follow up, and a lower probability of major depression at follow up (0.46, 0.24 to 0.86). The incremental cost of feedback plus care management was about $80 per patient. Monitoring and feedback to doctors yielded no significant benefits for patients in primary care starting antidepressant treatment. A program of systematic follow up and care management by telephone, however, significantly improved outcomes at modest cost.