In this study, we selected 58 styrene-exposed workers, measured personal styrene exposure, evaluated genotypes relevant drug-metabolizing enzymes (CYP2E1, EPHX1, GSTM1 and GSTT1) which may explain the variability in the urinary metabolite excretion. The results showed that, in different levels of styrene exposure groups, there is a significant association between urinary metabolites and some genotypes of styrene-metabolizing enzymes, including CYP2E1 (5-flanking region, RsaI/PstI), GSTM1(gene deletions) and EPHX1(predicted activity).