A workshop was held on 7-8 March 2001 in Orlando, Florida, to review the state-of-thescience in the application of genomic technologies in toxicology, ecotoxicology, and molecular epidemiology and the importance of these new developments in understanding the potential impacts of chemicals on humans and the environment. Ethical, legal, and regulatory issues and their influence on the direction and application of genomic research were also discussed. The workshop was sponsored by the International Council of Chemical Associations, which is a council of leading trade associations representing chemical manufacturers worldwide. The workshop was attended by more than 80 representatives from industry, academia, and various government agencies from the United States, Canada, Europe, and Japan.This report highlights the issues and recommendations discussed in each of the three areas: toxicology (including ecotoxicology), epidemiology, and ethical, social, and legal issues. Although the workshop presentations described genomics, proteomics, metabonomics, transcriptomics, and associated bioinformatics technologies (collectively referred to in this report as "omics") and the applications of the technologies for risk assessment and epidemiology, the reader is referred to Corton et al. (1999), Afshari et al. (1999), European Centre for Ecotoxicology and Toxicology of Chemicals (2001), and the National Institute of Environmental Health Sciences (NIEHS), National Center for Toxicogenomics (2001) for background information.Four overarching themes emerged from the workshop:• "Omics" technology should be used within a framework of toxicology and epidemiology principles so that it can be applied in a context that is understood for risk assessment.• Effective application of "omics" to epidemiology studies will require suitable biologic samples from large and diverse population groups at relevant time periods of exposure.• Discussion from ethical, social, and legal perspectives highlighted the fact that the use of "omics" technology will require the involvement of all stakeholder communities (i.e., research, academic, regulatory, public, and industry).• Recommendations for research and future use are broadly applicable across government, industry, and academia. A unified research agenda as applied to toxicology and epidemiology is urgently needed for the regulatory and scientific communities to realize the potential power and benefits of these new technologies. It was recognized that "omics" have the potential to reduce uncertainties in risk assessment and facilitate rapid assessments of a chemical's toxic potential. However, there is a critical need to establish relationships between gene expression data and toxicologic changes, enabling an integration of "omics" information with known toxicologic measures and other approaches to a better understanding of mechanism of chemical effects on biologic systems. In the interim, "omics" findings will likely be misinterpreted, because no guidelines currently exist for correlating quantitativ...