OBJECTIVE: In this study, the exposure levels of polycyclic aromatic hydrocarbons (PAHs) and urinary 1-hydroxypyrene(1-OHP) were surveyed among the workers using coal tar paint. METHOD: The study subjects for the exposed group were 107 male coal tar workers in 10 factories, and for the comparison group were 201 male clerk workers who had never been exposed to coal tar paint. Ambient PAHs, and pre-shift and end-shift urinary 1-OHP were sample and 16 PAHs were analysed. Smoking history was recorded during the survey day. RESULTS: The geometric mean of ambient concentration of total PAHs was 120.17 microgram/m3. Naphthalene had the highest level among the 16 PAHs. The pre-shift 1-OHP in the exposed group (8.89 micro mol/mol creatinine) was significantly higher than that in the control group (0.29 micro mol/mol creatinine). The end-shift 1-OHP in the exposed group (19.02 micro mol/mol creatinine) was significantly higher than that in the pre-shift (8.89 micro mol/mol creatinine) (Ed- confirm). 1-OHP of smokers was significantly higher than that of non-smokers in both groups. The difference between pre-shift and end-shift 1-OHP in smokers (12.40 micro mol/mol creatinine) was twice as high as that in non-smokers (6.06 micro mol/mol creatinine). The difference of 1-OHP between smokers and nonsmokers was 7.59 micro mol/mol creatinine in pre-shift and 13.96 micro mol/mol creatinine in end-shift. Thus, the effect of smoking and exposure to PAHs on 1-OHP may not be additive. In regression analysis for 1-OHP, the significant independent variables were pre-shift 1-OHP and PAHs. The direction of these variables was positive. When the analysis was performed in workers exposed to higher PAHs, smoking was significant independent variable. CONCLUSION: The above results suggest that not only ambient PAHs but also smoking, one of the most important non-occupational PAHs source, influenced the level of 1-OHP. Moreover, the effect of smoking to 1-OHP changed according to the exposure level of PAHs.