It is now possible to identify biochemical and/or cellular changes in humans due to exposure to an environmental toxin. These changes are called biomarkers and are currently used in research studies to identify individuals exposed to specific toxic substances. Advances in the field of biomarker technology may have important implications for the detection, prevention, and treatment of certain diseases in children. This technology may enable physicians to screen children who have no clinically detectable illness for evidence of exposure to specific toxins. Such information could lead to implementation of preventive measures and development of new therapeutic strategies. However, several important issues, including potential adverse consequences resulting from the widespread use of this technology, must be considered prior to its utilization within a clinical setting. Leaders of the pediatric and public health communities should recognize the paucity of scientific data in the pediatric environmental health area, and new approaches to this important aspect of child health should be developed. This article will address several of the issues involved in pediatric environmental health and consider questions that should be answered as the potential for technology transfer becomes a reality.