This report was prepared by the Center for Disease Prevention and Health Promotion in the Institute for Health and Productivity Management as part of an effort to improve understanding of the connection between employee health and performance and to begin to identify new strategies through which treating health as an investment in human capital can lead to greater business success. Computer database searches of peer-reviewed literature published between 1993 and 1998 and manual reviews of 20 journals were used to identify research on the link between employee health and performance. Data was extracted to summarize the overall findings on the magnitude of health problems addressed by health promotion and disease prevention programs, and the impact of interventions on improving health risk, reducing medical care cost, and improving worker performance. From this summary, major conclusions on early detection of disease, the impact of behavior change programs, and appropriate care-seeking were drawn. This systematic review is supplemented with summaries of 15 seminal articles and descriptions of five leading-practices programs. The influence of developments in work/family issues, complementary and alternative medicine, and quality of care and health outcomes research are briefly discussed. Finally, a conceptual framework for studying the impact of health and productivity is described.