Transforming small independent practices to patient-centered medical homes is widely believed to be a critical step in reforming the US health care system. Our team has conducted research on improving primary care practices for more than fifteen years. We have found four characteristics of small primary care practices that seriously inhibit their ability to make the transformation to this new care model. We found that small practices were extremely physician-centric, lacked meaningful communication among physicians, were dominated by authoritarian leadership behavior, and were underserved by midlevel clinicians who had been cast into unimaginative roles. Our analysis suggests that in addition to payment reform, a shift in the mind-set of primary care physicians is needed. Unless primary care physicians can adopt new mental models and think in new ways about themselves and their practices, it will be very difficult for them and their practices to create innovative care teams, become learning organizations, and act as good citizens within the health care neighborhood.