The growing number of laboratories performing chemical analysis of environmental lead has prompted an increased demand for reference materials. The use of reference materials for benchmarking the accuracy of analytical methods is important for establishing measurement quality for within and between laboratories. This paper describes the development of a variety of NIST Standard Reference Materials and other reference materials such as lead in blood, lead-based paint films, a series of powdered lead-based paints containing different lead levels, lead in household dust, and lead in simulated human tibia.