Paraoxonase1 (PON1) gene polymorphisms were implicated as risk factors for Parkinson's disease (PD), but the results of case-control studies that investigated these associations were controversial. In order to provide an answer to these contradictory results, a meta-analysis of all available studies relating the PON1-55M/L and PON1-192Q/R polymorphisms to the risk of developing PD was conducted. The racial descent of the populations in these studies was Caucasian and Asian. The meta-analysis revealed that there was an association of the PON1-55M allele and the risk of developing PD relative to the L allele: fixed effects pooled odds ratio (OR)=1.32 [95%CI (1.10-1.59)]. In addition, there was evidence of association for the genotypic contrast PON1-55MM+LM relative to PON1-55LL: fixed effects OR=1.50 [95%CI (1.16-1.95)]. There was no significant association between PON1-192Q/R alleles and risk of developing PD: OR=1.09 [95%CI (0.93-1.26)]. There was no evidence for an association between the genotypic contrasts of PON1-192 and development of PD. The heterogeneity between studies and the publication bias were not significant ( P> or =0.10) in either polymorphism. Therefore, the pooled results of the meta-analysis supported that there was an association between PON1-55M/L polymorphism and PD and that PON1-192Q/R polymorphism was unlikely to be a major risk factor for susceptibility to PD.