In this study, the biochemical role of genetic polymorphism in modulating urinary excretion of benzene metabolite as phenol level has been investigated in 90 workers exposed to benzene in the petroleum refinery plant of Korea. The mean concentration of volatile benzene in the refinery environment was 0.042 mg/㎥ (SD, 0.069) and that of urinary phenol was 7.42 mg/g creatinine (SD, 11.3). The frequencies of CYP2E1 genotypes, namely CYP2E1$^*1$/$^*1$, CYP2E1$^*1$/$^*2$ and CYP2E1$^*2$/$^*2$ were 2.2% (2 subjects), 6.7% (G subjects) and 91.1% (85 subjects), respectively, and allele frequencies for CYP2E1$^*1$ and CYP2E1$^*2$ were 0.06 and 0.94. The airborne benzene concentration was significantly related to the concentration of phenol in urine (r = 0.640, p < 0.01). The urinary phenol level was significantly correlated with CYP2E1$^*2$/$^*2$ (r = 0.590, p < 0.05). The various biological (i.e. age and liver function parameters) or lifestyle factors (i.e. medication, smoking, alcohol and coffee intake), also taken into account as potential confounders, did not influence the correlation found. These results suggested that CYP2E1 genotypes might play an important role in the metabolism of benzene.