Background/Aim: Reactive oxygen species (ROS) are involved in the development of certain neuropsychiatric disorders. Paraoxonase 1 (PON1) activity has been suggested to be adversely related to oxidative stress in plasma. The purpose of the present study was to demonstrate the relationship between serum PON1 activity and PON1 192 polymorphism in panic disorder (PD). Materials and Methods: Fourty-two patients with PD and 46 healthy controls were included in this study. PON1 192 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. PON1 activity was measured by spectrophotometric assay of p-nitrophenol production following the addition of paraoxon. Results: PON1 192 AA genotype and A allele in PD were significantly higher than in the control group, whereas the B allele was found to be significantly higher in the control group. Patients with panic disorder have lower PON1 activity than the control group. Conclusion: The PON1 192 AA genotype may increase the risk of PD depending on lipid peroxidation.