More and more healthcare organizations are recognizing that clinical integration of providers is a prerequisite to care coordination, population health management, and accountable care organizations. They also know that patient centered medical homes—the building blocks of ACOs—can thrive only in patient-centered medical neighborhoods where specialists collaborate with primary care physicians. For this cooperation to be truly effective, all of these providers must be clinically integrated. This paper explains the components of clinical integration and summarizes the kinds of information technology required for its implementation. Case studies of organizations that are building the necessary infrastructure are also included.