The patient-centered medical home (PCMH) is an innovative care model for the provision of primary care that is being rapidly adopted in the U.S. with the support of federal agencies and professional organizations. Its goal is to provide comprehensive, patient-centered care with increased access, quality, and efficiency. Diabetes, as a common, costly, chronic disease that requires ongoing management by patients and providers, is a condition that is frequently monitored as a test case in PCMH implementations. While in theory a PCMH care model that supports patient engagement and between-visit care may help improve diabetes care delivery and outcomes, the success of this approach may depend largely upon the specific strategies used and implementation approach. The cost-effectiveness of diabetes care in the PCMH model is not yet clear. Interventions have been most effective and most cost-effective for those with the poorest diabetes management at baseline.