One of the principal responsibilities of the U.S. Environmental Protection Agency is to conduct research necessary to maintain an adequate scientific and technological data base on which to establish the standards, regulations and implementation actions required by various congressional acts. This paper discusses the two legislative mandates; the Clean Air Act and the Toxic Substances Control Act, because most of our research related to immunotoxicity has been done to provide data for these two. The use of immunologic data for regulation of environmental pollutants is obviously in its infancy. Major factors that affect the usefulness of immunologic data for regulatory decisionmaking and describe an approach we are presently developing to answer questions related to immunotoxicity of chemicals are discussed in this paper.