BACKGROUND: Telemedicine-based diabetes management improves outcomes versus clinic care but is seldom implemented by healthcare systems. In order to advance telemedicine-based management as a practical option for veterans with persistent poorly controlled diabetes mellitus (PPDM) despite clinic-based care, we evaluated a comprehensive telemedicine intervention that we specifically designed for delivery using existing Veterans Health Administration (VHA) clinical staffing and equipment. MATERIALS AND METHODS: We conducted a 6-month randomized trial among 50 veterans with PPDM; all maintained hemoglobin A1c (HbA1c) levels continuously >9.0% for >1 year despite clinic-based management. Participants received usual care or a telemedicine intervention combining telemonitoring, medication management, self-management support, and depression management; existing VHA clinical staff delivered the intervention. Using linear mixed models, we examined HbA1c, diabetes self-care (measured by the Self-Care Inventory-Revised questionnaire), depression, and blood pressure. RESULTS: At baseline, the model-estimated common HbA1c intercept was 10.5%. By 6 months, estimated HbA1c had improved by 1.3% for intervention participants and 0.3% for usual care (estimated difference, -1.0%, 95% confidence interval [CI], -2.0%, 0.0%; p = 0.050). Intervention participants' diabetes self-care (estimated difference, 7.0; 95% CI, 0.1, 14.0; p = 0.047), systolic blood pressure (-7.7 mm Hg; 95% CI, -14.8, -0.6; p = 0.035), and diastolic blood pressure (-5.6 mm Hg; 95% CI, -9.9, -1.2; p = 0.013) were improved versus usual care by 6 months. Depressive symptoms were similar between groups. CONCLUSIONS: A comprehensive telemedicine intervention improved outcomes among veterans with PPDM despite clinic-based care. Because we specifically designed this intervention with scalability in mind, it may represent a practical, real-world strategy to reduce the burden of poor diabetes control among veterans.