In the United States many of the cardinal features of primary care are absent. Medical practitioners usually do not provide services to a defined panel of patients and are not distributed according to the extent or type of health needs in the population or to population size. Findings from research indicate the benefits of longitudinality, comprehensiveness, first contact care, and coordination. Some of the new developments in the organization and financing of services may facilitate the attainment of some of these characteristics, but the implementation of even a rudimentary primary care system will require a greater commitment to the training of primary care personnel and better deployment of resources. In the absence of a societal commitment to a health system based upon levels of care and community orientation, a research agenda to determine the benefits and costs of various alternative approaches is suggested.