This article identifies new research and policy directions for the field of worksite health in the context of the changing American workplace. These directions are viewed from an ecological perspective on worksite health and are organized around three major themes: (1) the joint influence of physical and social environmental factors on occupational health, (2) the effects of nonoccupational settings (e.g., households, the health care system) on employee well-being and the implications of recent changes in these settings for worksite health programs, and (3) methodological issues in the design and evaluation of worksite health programs. Developments in these areas suggest that the field of worksite health may be undergoing a fundamental paradigm shift away from individually oriented wellness programs (provided at the worksite and aimed primarily at changing employees' health behavior) and toward broader formulations emphasizing the joint impact of the physical and social environment at work, job-person fit, and work policies on employee well-being.