Abstract: Objective To explore the relationship between vinyl chloride monomer(VCM)exposure and P53 genotype polymorphism and mRNA expression of P53 in lymphocytes among workers exposed to VCM.Methods Seventy-five occupationally VCM-exposed workers(exposure period more than one year)and 43 controls without history of exposure to VCM or other toxican tswere enrolled in this study.The quantity of gene mRN Aexpre ssion was detected with real-time PCR (SYBR Green I).Results The level of P53 mRNA relative expression was 4.674(0.965,18.163)in VCM-exposed workers and 16.400(9.600,26.800)in unexposed controls.After adjustment for age,robust multiple regressionind icated that the P53 mRNA expression of VCM-exposed workers was significantly lower than that of the non-exposed group (χ²=53.42,P<0.0001).The results also showed that the cumulative exposure dose and P53 genotype had no effect on mRNA expression of P53 in VCM-exposed workers.Conclusion The mRNA expression of P53 in per ipherallym phocyte is significantly decreased in VCM exposed workers compared to unexpo sed controls.