Abstract: The aim of this study was evaluation of exposed to toluene and compare levels of hippuric acid and o-Cresol in taxi drivers, petrol station workers, car painters with a control group in West of Iran. The urinary o-creasol and toluene in air were analyzed by a gas chromatography and hippuric acid was extracted from urine and analyzed by high performance liquid chromatography. The significant differences in the levels of urinary o-Cresol were found in painters and petrol station workers compared to the control group (p<0.005). There was no significant correlation between toluene in air and biomarkers for taxi drivers. The lowest toluene concentration at which urinary hippuric acid increased to a measurable level was approximately 25 to 35 ppm and for o-Cresol was 2 ppm. In conclusion our results was showed that o-Cresol and hippuric acid could separate the exposed to toluene from the non-exposed when toluene in breathing zone of subjects was greater than 3 and 35 ppm, respectively. Hippuric acid and o-Cresol are not suitable biomarkers for occupations such as drivers that exposure to toluene in low concentration.