Although Congress recently passed health insurance reform legislation, the real catalyst for change in the health care delivery system, the author's argue, will be changes to the reimbursement model. To rein in increasing costs, the Centers for Medicare and Medicaid aims to move Medicare from the current fee-for-service model to a reimbursement approach that shifts the risk to providers and encourages greater accountability both for the cost and the quality of care. This level of increased accountability can only be achieved by clinical integration among health care providers. Central to this reorganized delivery model are primary care providers who coordinate and organize the care of their patients, using best practices and evidence-based medicine while respecting the patient's values, wishes, and dictates. Thus, the authors ask whether primary care physicians will be available in sufficient numbers and if they will be adequately and appropriately trained to take on this role. Most workforce researchers report inadequate numbers of primary care doctors today, a shortage that will only be exacerbated in the future. Even more ominously, the authors argue that primary care physicians being trained today will not have the requisite skills to fulfill their contemplated responsibilities because of a variety of factors that encourage fragmentation of care. If this training issue is not debated vigorously to determine new and appropriate training approaches, the future workforce may eventually have the appropriate number of physicians but inadequately trained individuals, a situation that would doom any effort at system reform.