The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) conducted an evaluation of the potential for ethylene glycol (EG) to cause adverse effects on reproduction and development in humans. EG was selected for evaluation due to recent toxicity and occupational exposure information and widespread exposure in the general public. EG is a small, hydroxy-substituted hydrocarbon used as a chemical intermediate in the production of polyester compounds. It is also found in automotive anti-freeze, industrial coolants, hydraulic fluids, and windshield deicer fluids. The results of this evaluation on EG are published in a NTP-CERHR monograph which includes: 1) the Expert Panel Report on the Reproductive and Developmental Toxicity of Ethylene Glycol, 2) the NTP Brief, and 3) public comments received on the Expert Panel Report. As stated in the NTP Brief, the NTP reached the following conclusions regarding the possible effects of exposure to EG on human development and reproduction based on the conclusions of the NTP-CERHR Expert Panel Report and the public comments received on that report. These conclusions concurred with those of the expert panel. First, although EG could possibly affect human development if exposures are sufficiently high, there is negligible concern for developmental effects in humans at current proposed/estimated exposure levels. There is no direct evidence that exposure of people to EG adversely affects reproduction or development, but studies reviewed by the expert panel show that oral exposure to high doses of EG can adversely affect development in mice and rats. These studies indicate doses that exceed saturation of the glycolic acid metabolism are needed to produce developmental toxicity. Proposed exposure scenarios constructed by the expert panel and current proposed/estimated exposure levels suggest that human exposures are at least 100- to 1000-fold lower than the dose expected to result in metabolic saturation in humans (estimated at 125 mg/kg body weight). Second, there is negligible concern for reproductive effects in humans. Studies evaluated by the expert panel showed that, at high exposure levels, there is no evidence of adverse reproductive effects in mice or rats. NTP-CERHR monographs are transmitted to federal and state agencies, interested parties, and the public and are available electronically in PDF format on the CERHR web site (http://cerhr.niehs.nih.gov) and in printed text or CD-ROM from the CERHR (National Institute of Environmental Health Sciences, P.O. Box 12233, MD EC-32, Research Triangle Park, NC; fax: 919-316-4511).