Medical practice redesign refers to the intentional efforts to improve practice processes and outcomes. Efforts to redesign office-based medical care go back some forty years. We divide the history of practice redesign into three overlapping phases: basic investigation, model development, and dissemination. The "medical home" movement in primary care has accelerated this dissemination phase. The acceleration and scaling up of efforts in practice redesign that have resulted from interest in the medical home present substantial opportunities and challenges for the medical profession and the U.S. health care system. We review the history and extract lessons to inform today's medical practice redesign efforts.