BACKGROUND: Primary care treatment of depression needs improvement. OBJECTIVE: To evaluate the efficacy of 2 augmentations to antidepressant drug treatment. DESIGN: Randomized trial comparing usual care, telehealth care, and telehealth care plus peer support; assessments were conducted at baseline, 6 weeks, and 6 months. SETTING: Two managed care adult primary care clinics. PARTICIPANTS: A total of 302 patients starting antidepressant drug therapy. INTERVENTIONS: For telehealth care: emotional support and focused behavioral interventions in ten 6-minute calls during 4 months by primary care nurses; and for peer support: telephone and in-person supportive contacts by trained health plan members recovered from depression. MAIN OUTCOME MEASURES: For depression: the Hamilton Depression Rating Scale and the Beck Depression Inventory; and for mental and physical functioning: the SF-12 Mental and Physical Composite Scales and treatment satisfaction. RESULTS: Nurse-based telehealth patients with or without peer support more often experienced 50% improvement on the Hamilton Depression Rating Scale at 6 weeks (50% vs 37%; P =.01) and 6 months (57% vs 38%; P =.003) and on the Beck Depression Inventory at 6 months (48% vs 37%; P =. 05) and greater quantitative reduction in symptom scores on the Hamilton scale at 6 months (10.38 vs 8.12; P =.006). Telehealth care improved mental functioning at 6 weeks (47.07 vs 42.64; P =.004) and treatment satisfaction at 6 weeks (4.41 vs 4.17; P =.004) and 6 months (4.20 vs 3.94; P =.001). Adding peer support to telehealth care did not improve the primary outcomes. CONCLUSION: Nurse telehealth care improves clinical outcomes of antidepressant drug treatment and patient satisfaction and fits well within busy primary care settings.