INTRODUCTION: In 2006, the Massachusetts League of Community Health Centers convened a collaborative to systematically improve health care delivery for patients with diabetes in 17 community health centers. Our goal was to identify facilitators of and barriers to success reported by teams that participated in this collaborative. METHODS: The collaborative's activities lasted 13 months. At their conclusion, we interviewed participating team members. We asked about their teams' successes, challenges, and take-home messages for future collaborative efforts. We organized their responses into common themes by using the Chronic Care Model as a framework. RESULTS: Themes that emerged as facilitators of success included shifting clinic focus to more actively involve patients and to promote their self-management; improving the understanding and implementation of professional guidelines; and expanding staff roles to accommodate these goals. Patient registries were perceived as beneficial but lacking adequate technical support. Other barriers were staffing and time constraints. CONCLUSION: Cooperative efforts to improve health care delivery for people with diabetes may benefit from educating the health care team about guidelines, establishing a stronger role for the patient as part of the health care team, and providing adequate technical instruction and support for the use of clinical databases.