A university-related prepaid group practice was established in Columbia, Maryland, in 1969, by the Johns Hopkins Medical Institutions with the cooperation of the Connecticut General Life Insurance Company. Objectives were based on the traditional triad of service, teaching and research. The effort continues. There has been visible success in the achievement of each of the objectives. It is evident, however, that the development of the Columbia Medical Plan would have been facilitated if there had been a larger population base in which to market membership in the Plan, if marketing had been under the direction of the health-care provider, and if the burden of the building and running of a hospital had not been assumed. Overall, the experience suggests that the Health Maintenance Organization movement has only modest ultimate potential as an option in health-care delivery in the current economic milieu of American medicine.