This study was carried out to investigate the correlation between toluene in air and hippuric acid in human urine, which is based on the results of the health check-in and the measure of working environment, was investigated for two years. The concentration of toluene in air for the five working places in Yang-San area were ranged from 39.05±10.31 ppm to 4.04±3.38ppm and the mean value of those was 16.89±14.76ppm. The mean value was 16.89±14.76ppm which is below the permissible limit of toluene. The concentration of hippuric acid(HA) in the worker's urine were between 0.47g/ℓ and 0.76g/ℓ. There was mutual correlation (r=0.94) between the concentration of toluene in air and that of hippuric acid in urine. In case of male workers, the mean value of hippuric acid in urine was 0.56g/ℓ and the female workers was 0.57g/ℓ that showed higher than the male's. However, there was no relationship between the workshop and the distinction of sex. From the mean value of toluene in air(T) and that of hippuric acid(H), we obtained the formula, H= 0.3log T+0.235