The agenda for behavioral and social science research in cancer prevention and control needs to be assessed and interpreted within the context of a changing health care system. These changes present potential opportunities and barriers to an evolving research agenda. Opportunities include access to defined populations and providers, emphasis on clinical outcomes, and access to clinical and financial data. Barriers include intense competition among providers and an overriding emphasis on cost containment. To meet these challenges, attention needs to be given to developing new partnerships with provider organizations, emphasizing interdisciplinary cooperation and training, and reassessing underlying behavioral assumptions and models.