This Study was performed to investigate the effect of foods containing benzoic acid on the urinary hippuric acid concentration in the toluene exposed workers. The urinary hippuric acid concentration were measured at 0, 30, 60, 90, 120, and 150 minute after intake of soft drink and bread containing benzoic .acid: in volunteers,: who did not have been exposed toluene occupationally. After that urinary hippuric: acids also were measured at the end of shift in toluene exposed workers. And also the concentration of toluene in air were analysed! by gas chromatography. So the relationships between urinary hippuric acid concentration and age, work duration, concentration of toluene in air and intake of benzoic acid containing food were observed. The results were as follows: 1. The urinary hippuric acid concentration reached the highest level at 30 minute after intake of soft drink with bread at a level of 1.41g/g creatinine and soft drink; alone at a level of 1.04g/g creatinine which contained benzoic acid among unexposed toluene, and then gradually decreased. 2. In toluene exposed group no significant effect of general; characteristics siich; as gender, age, work duration, drinking and smoking on urinary: hippuric acid concentration was showed in toluene exposed group. 3. The mean value of urinary hippuric acid concentration of group taking benzoic acid containing foods was significantly higher than that of group not taking. 4. Multiple regression analysis showed that toluene concentration in .air and benzoic acid containing foods were together significantly influence on urinary ; hippuric acid concentration. And the function between variables is Y = 0.014Tpluene +0.489Benzoic acid +0.745 and the contribution rates were 31%. In conclusion, it was suggested that the information on intake of benzoic acid containing foods should be considered in measurement of urinary hippuric acid for the more accurate toluene exposure evaluation.