Objectives : To identify the relationship between the use of medical services by workers with three types of respiratory diseases(total respiratory diseases, acute upper respiratory infections and chronic lower respiratory diseases) and exposure to hazardous agents after controlling for other factors affecting medical services use, such as characteristics of the enterprises(scale, industry type) and employee demographics (sex, age). Methods : The study population comprised 28,882 workers who had undergone general or special medical examinations at the industrial health center at least once between Jan 1995 and Dec 1997 and had possessed medical insurance during the period. We combined medical examination data with medical insurance data in order to analyze the relationship between exposure to hazardous agents and respiratory diseases, Results : Among the 28,882 study subjects, 17,454 employees(60.4%) used medical services more than once during 3-year study period, owing to more than one kind of respiratory diseases. In logistic regression analysis, sex, age and the size of the enterprises proved to be significant variables on the use of medical services for all three types of respiratory disease; The use of medical services increased with employee age. Women used more medical services than men and the employees in the large-scale enterprises used more services than employees in small-scale enterprises. However, exposure to dust or organic solvents did not affect medical service use due to total respiratory diseases or acute upper respiratory infections. Only in the case of chronic lower respiratory diseases did workers exposed to dusts(OR=1.12, 95% CI=1.01-1.24) or organic solvents(OR=1.19, 95% CI=1.05-1.35) use more medical services than those not exposed. Conclusions : Workers exposed to dusts or organic solvents are particularly apt to suffer from chronic lower respiratory diseases and use medical services more often than those not exposed. That is, chronic exposure to hazardous agents such as dusts and organic solvents is believed to be harmful and to cause respiratory symptoms and diseases.