Surveillance for occupational safety and health problems has historically lagged behind that for infectious diseases. Adequate surveillance methods are essential in assessing the scope of health problems and in assigning priorities for intervention strategies; therefore, in recent years the National Institute for Occupational Safety and Health (NIOSH) has placed heavy emphasis on upgrading occupational health surveillance. Since direct surveillance of exposed workers has been shown to be a useful way to assess the prevalence of disease and to monitor trends, in 1984 NIOSH began an extensive survey of potential occupational exposures found at mine sites in the United States. The National Occupational Health Survey of Mining (NOHSM) is similar to the National Occupational Hazard Survey that NIOSH conducted during 1972-1974 and the follow-up National Occupational Exposure Survey conducted during 1981-1982, both of which, however, involved only general-industry worksites. NOHSM not only will identify potential exposures related to occupational lung diseases, which head the NIOSH list of 10 leading work-related diseases and injuries (1), but also will identify potential exposures that may lead to other conditions on the list. The present plans for NOHSM call for five segments of mine surveys, to last approximately 1 year each, with an expected completion date of 1989. This report describes the purposes of NOHSM and the methods used. Results will be published in subsequent articles, as they become available.