The Massachusetts Patient Centered Medical Home Initiative (MA PCMHI) is a statewide, multi-payer demonstration that seeks to transform 46 primary care practices into PCMHs. Clinical care management of high-risk patients is a key element of the PCMH and a new service for most primary care practices. Training for practices in the MA PCMHI includes the clinical care manager (CCM) role, identification/tracking of highest-risk patients, care plan development/implementation, care coordination, and communications. Content is delivered through learning collaborative sessions, monthly webinars and practice-based transformation facilitation. Assessment of progress towards implementation is made through practice-based data on clinical care management measures and self-assessment of transformation. At year one of implementation, averages for measures such as percentage of patients who received timely follow-up after hospitalizations and ED visits range 37%-63% with 35-40 of 46 practices reporting. The challenges that have hampered implementation include lack of: (1) EMR/registry functionality, (2) hospital to practice notification systems, (3) clarity of the CCM role and workflow, (4) risk stratification criteria for high-risk patients, and (5) adequate resources to support this service. An important lesson learned is that engaged leadership is critical to successful clinical care management implementation. Next steps include refinement of the practice-based self-assessment that is used as a monitoring and QI tool, and a pilot to study the coordination of payer-based and practice-based clinical care management.