The National Human Monitoring Program (NHMP) was established in 1967 within the U.S. Public Health Service to study changes in pesticide residues in the U.S. population. The primary activities of the NHMP are the National Human Adipose Tissue Survey (NHATS) and special studies that support other programs requiring data relevant to chemical exposures. The NHMP, including NHATS, was transferred to the Environmental Protection Agency (EPA) in 1970. The NHATS is now out of date and only partially fulfills its objectives. Design and management problems have been compounded by insufficient financial support for the changing and expanding objectives, and the overall quality of the NHATS has deteriorated. In 1987 EPA announced its intention to eliminate the NHMP. Congress responded by instructing EPA to retain the program, pending a review of its usefulness. EPA asked the National Research Council (NRC) to review and evaluate the effectiveness and potential applications of the NHMP. The report evaluates the current activities of the NHMP; identifies important scientific, technical, and programmatic issues; and makes recommendations regarding the design of the program and use of its products.