Background: This study was carried out for the purpose of comprehensively evaluating the mercury exposure level of residents in several areas and the correlation between hair mercury concentration and blood mercury concentration. Method: One thousand one hundred ninety seven subjects were sampled from 30 sites using random assignment sampling. We performed a questionnaire survey and measured the level of total mercury in hair and blood samples from all subjects. Results: The geometric mean concentrations of hair and blood mercury in all subjects were 1.27 mg/kg [95% confidence interval (CI): 1.23-1.32 mg/kg] and 5.24 ${mu}g/L$ [95% CI: 5.07-5.41 ${mu}g/L$], respectively. Male (1.56 mg/kg in hair, 6.00 ${mu}g/L$ in blood) was significantly higher than that of female (1.03 mg/kg in hair, 4.56 ${mu}g/L$ in blood), and the concentrations were elevated as age increased up to the 50s. Education, smoking, alcohol drinking, and using of pesticides were also shown to influence mercury concentrations in hair and blood. The ratio of hair/ blood mercury concentration was 261.3. The total mercury concentration in hair was identified to be significantly related with total mercury concentration in blood (r=0.814, p<0.001). Conclusion: The geometric mean concentrations of hair and blood mercury were higher than the levels provided in international recommendations. The total mercury concentration in hair was positively correlated with the concentration in blood. The results of this study suggest that hair mercury be considered as a useful tool for the evaluation of mercury exposure.