Various numbers of factors such as oxidative stress, neurotoxins, and pesticides have been implicated in its pathophysiology of Parkinson's disease (PD). Paraoxonas1 (PON1) metabolizes xenobiotics, including pesticides. Therefore, we surveyed the relationship between PON1 polymorphisms with its activities in the pathogenesis of Parkinson's disease..We investigated polymorphisms of the PON1 (L55M and Q192R) by PCR-RFLP assays; we also measure the levels of PON1, TAC (total antioxidant capacity) and TOS (total oxidant status) with ELISA (Enzyme-linked immunosorbent assay) and spectrophotometric method for their activities.Paraoxonase and arylesterase activity of PON1 as well as their concentrations were lower in patients with PD compared with control group, but from the view of the specific activity, it was not significant between two groups. In the compare of TAC, TOS, and OSI, the TOS and OSI were higher in the patients than controls, while patients had lower levels of TAC compared with controls. Serum PON1 concentrations and activities were higher in LL (comparison with LM and MM) and RR (comparison with QR and QQ) genotypes while we did not observe any significant differences in arylesterase levels among mentioned polymorphisms.In the current study, we reported associations between PON1 polymorphisms (55, 192) and enzyme activities in Parkinson's disease as there was a significant reduction in PON1 levels in patients with Parkinson compared with healthy. Taken together, paraoxonase enzyme in subjects with different genotypes could be a potential biomarker for determining the severity and prognosis of Parkinson. However, more studies are needed to clarify its clinical values. Key words: Parkinson's disease; paraoxonase1; Polymorphism.