In response to poor coordination among health and social service providers, health care consortia have emerged in many areas of the United States. Consortia link multiple providers in a common structure to create comprehensive systems of care. They can be formally structured or informal combinations of providers that engage in coordination but otherwise do not comprise an independent organization. The functions most common among all types of consortia are shared services and service coordination; however, a number of consortia also operate outreach/education programs. Consortia represent an innovative response to the need both for vertical integration--case management of all levels of care--and horizontal integration to prevent duplication among primary care providers. We outline the history of consortia in which federally-funded community health centers have participated. We also suggest an analytical framework for the various types of consortia; discuss lessons learned about building and maintaining consortia; and provide preliminary outcome data.