Two primary forces drive EPA's biomarker research efforts: advances in the state-of-the-science and the need to reduce uncertainties in health risk assessment. Scientific advances in molecular biology over the past few decades have resulted in an increased understanding of life processes. This knowledge coupled with advances in clinical chemistry, toxicology, and occupational medicine provides scientists with techniques to evaluate human tissues, fluids and breath samples for evidence of chemical exposure and biological effects. EPA's office of Research and Development evaluated the current status of biomarkers with respect to risk assessment needs to develop an EPA health research strategy for biomarkers. The initial focus will be on measures for exposure evaluation. The paper discusses EPA's biomarker strategy emphasizing ways biomarkers can be employed in TEAM Studies.