Practice facilitators (PFs) are health care professionals, who assist primary care practices in research and quality improvement activities. Their work goes beyond data collection and feedback and includes practice enhancement methods to facilitate system-level changes. PFs provide a framework for translating research into practice by building relationships, improving communication, facilitating change, and sharing resources in practice-based research networks (PBRNs). The work of PFs is funded from a variety of sources, including academic grants and renewable contracts with national, state, and local health care agencies. Limited information is available on cost-effectiveness of PF interventions. This article provides examples of how the PF model was implemented in 4 PBRNs in the United States.