The use of exposure registries for cohort studies of occupational exposures was reviewed. The purposes of the registries included delineation, notification and follow up of a risk population with regard to determination of exposure disease relationships; primary and secondary prevention methods; appropriate medical surveillance, and social, legal, and economic support; and provision of a base for political action relevant to the exposure. Legislation mandating the development of exposure registries included the Occupational Safety and Health Act of 1970, the Health Services Research, Health Statistics and Health Care Technology Act of 1978, and the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. Specific recommendations for the establishment and operation of exposure registries were included in a study conducted by the National Center for Health Statistics regarding the issues involved in developing a federal system to locate individuals exposed to hazardous substances, determining the effect of such exposures on their health, and helping them obtain access to appropriate medical treatment. The exposure registry framework of Harris was reviewed as a proposed model, and the transfer of information to the primary medical care delivery system, biological markers of exposure and methods of chemoprevention, and responsibility for the registry were discussed.