Residents who live near petrochemical industrial areas risk exposure to a variety of petrochemicals, including benzene and benzene-containing liquids. It is a serious concern because benzene is a human carcinogen naturally present in petroleum and gasoline. The aim of this study was to assess the exposure to benzene, measured by personal/indoor/outdoor air sampling, and to estimate the relationship between the air samples and biological monitoring data. Through biological monitoring, we investigated s-phenylmercapturic acid(s-PMA), minor urinary metabolites of benzene, and benzene in blood. The external benezene exposure of 115 subjects was measured with passive dosimeters and urinary s-PMA and blood-benzene were determined by GC/MS. The mean concentration of benzene in the breathing zone or residents was 6.3 μg/m^3, slightly higher than indoor or outdoor concentrations. Personal, indoor and outdoor concentrations of benzene were significantly correlated to each other. s-PMA was affected by personal exposure(p<0.05)and was differed according to aqe(p<0.01)and residence time(p<0.05). Blood benzene was not affected by external benzene during these periods.