The intramural gerontological research program in the National Institutes of Health underwent a substantial growth after its creation within the precincts of the Baltimore City Hospitals in 1940. This paper analyzes its development and the associated problems of its early years. Gerontologists aimed at improving the social and economic life of the elderly through scientific research. With this aim in mind, they conducted various investigations using the indigent aged patients of the Baltimore City Hospitals. Yet the scientists of aging, who hoped to eliminate negative social factors that might bias their research and heighten the confusion between pathology and aging per se, eventually stopped using these patients in the hospital as human subjects. Instead they sought educated affluent subjects in order to eliminate the impact of poverty. By doing so, however, they introduced a new source of social bias to their work, especially within the novel project begun in 1958, the Baltimore Longitudinal Study of Aging. This article thus examines the context of the development of gerontologists' research by analyzing their agenda, institutional environment, and research subjects in the 1940s and the 1950s.