In this report, the Committee on the Toxicological Effects of Methylmercury of the NRC independently reviewed the reference dose for MeHg. The committee reviewed the available toxicological, epidemiological, and exposure data (from food and water) and determined the appropriateness of the critical study, end points of toxicity, and uncertainty factors used by EPA in the derivation of the reference dose for MeHg. The committee was also asked to identify data gaps and make recommendations for future research.