A symposium entitled Immunomodulation by Metals was held at the 32nd Annual Meeting of the Society of Toxicology (SOT) in New Orleans, Louisiana. The symposium was co-sponsored by the Immunotoxicology and Metals Specialty Sections of SOT and was designed to describe the types of adverse immunological reactions which occur in response to environmental and/or occupational exposure to metals. Epidemiological evidence and underlying mechanisms responsible for the observed alterations were also discussed. The following is a summary of each of the individual presentations.