OBJECTIVE To test the relationship between the presence of recommended chronic care model systems and the degree of integration among large medical groups. STUDY DESIGN Cross-sectional survey in 2007 completed by medical directors of medical groups nationally with at least 100 physicians and a range of medical services and who had also participated in the National Survey of Physician Organizations. METHODS We recruited 111 medical directors among 123 who were eligible. The survey asked about the medical group's structural, financial, and functional aspects of integrated care, as well as the presence and use of practice systems for chronic disease care as measured by the Physician Practice Connections-Readiness Survey (PPC-RS). The analysis tested the association between integration measures and the presence of practice systems, controlling for medical group attributes. RESULTS Ninety-seven completed surveys were returned (89.0% of 109 medical directors eligible). Measures of integration and practice systems varied widely among the medical groups. The total PPC-RS score correlated with each measure of integration but most highly with functional integration (r = 0.53, P <.01). The strongest PPC-RS component score correlations were for delivery systems redesign (r = 0.27-0.52, P <.01) and for decision support (r = 0.21-0.46, P <.05). Adjusting for organizational characteristics had little effect on these relationships. CONCLUSION As measured by these scales, integration seems to be related to the presence of practice systems components of the chronic care model, although simply having the potential for integration (structure and finance) is much less strongly related than evidence of functional integration.