One of the principal goals of the Office of Behavioral and Social Sciences Research at the National Institutes of Health is to facilitate interdisciplinary research between social, behavioral, and biomedical scientists. The purpose of this paper is to provide a framework for such interdisciplinary health research. The essence of this framework is the concept of levels of analysis in the health sciences. These levels include the social/environment, behavioral/psychological, organ systems, cellular, and molecular. The interdependence of these five levels of analysis suggests that advances in the health sciences may be accelerated by a more integrated, multilevel approach to research. The principles of integrated, multilevel research are outlined, and examples of research that support this approach are presented. Finally, some of the activities of the Office of Behavioral and Social Sciences Research that will further interdisciplinary research across levels of analysis are summarized.