Pneumoconiosis, especially Coal-workers' Pneumoconi6sis(GWP), is the principal occupation-related disease in Korea because of the large number of affected workers. Coal mines and miners have been reduced abruptly during recent 8 years, but coal mining should be kept in Korea. Recently, pneumoconiotic workers are increasing in manufacturing industry. It is necessary to know the characteristics of CWP to prevent the development of CWP and manage employed or retired pneumoconiotic workers. Furthermore, it is also necessary to study CWP to protect workers from pneumoconiosis in manufacturing industry. Of the total of 6,452 workers who were diagnosed as CWP initially during the 20 years from 1973 to 1992, X-ray category was as follows: category 1(35.2%), category 2(23.1%), suspicious (0/1 category, 13.4%), category 3(5.7%), large opacity (3.5%), unknown by. complete classification (19.1%). The patients' cardiopulmonary disability was as follows: no disability 79.3%, slight 14.2%, mild 4.1%, moderate 1.9%, severe 0.5%. The patients' X-ray category and disability were not related with the initially exposed age or job position, but their severity was positively related with the exposed duration that was adjusted by the initially exposed age. Also, the patients' X-ray category and disability had positive relationship each other. The cumulative exposure dose of silica/was more important than that'of respirable dust in the. development of large opacity CWP. The annual incidence density of CWP was 73.2 persons in 1982 and 75.8 persons in 1986per 10,000 person years. Afterthen it has been gradually decreasing and was in the range of 20-30 persons in the period of 1989-1992.