Technical Abstract: The availability of reliable validated exposure data is critical for assessing the causal relationships between exposure to endocrine-disrupting chemicals (EDCs). A review of the exposure of selected EDCs in humans and wildlife revealed that comparable data sets are primarily available from parts of Europe, North America, and to a lesser degree from a few other areas of the globe. Most exposure data are for the persistent, lipophilic organohalogen compounds, however, a paucity data sets exist for the less persistent EDCs, such as many pesticides, phthalate esters, nonylphenols and phytoestrogens. Exposure data sets which exist are primarily for external exposure (air, food, water) rather than internal exposure (blood, tissues). The limitations on exposure data to only few EDCs make assessments of their importance very difficult. Exposures to most organohalogens appear to be on the decline over the last 20 years. Generally, exposure data to EDCs for humans as well as wildlife at early life stages is lacking. Many EDCs exist as mixtures of isomers and homologues posing special measurement problems, such as the availability of standardized methods and chemical standards. Detection limits also vary widely between specific classes of EDCs, being biased in favor of low level detection of single-component organohalogens and other hydrophobic EDCs. Methods are generally not available at present for detecting and measuring certain EDCs at biologically relevant concentrations. These assessments are important so that policy makers and regulators can propose and implement effective pollutant control measures. 14. Interpretive Summary