ABSTRACT. Familial Mediterranean fever (FMF) is an autosomal recessive disorder and is the most frequent of the periodic febrile inflammatory syndromes. The pathogenesis of the disease is not completely understood, even though the FMF gene has been identified. Oxidative stress and inflammation may play a role in the pathogenesis of FMF. We investigated gene polymorphisms of the antioxidative enzymes, glutathione peroxidase (GPX) and paraoxonase (PON) in FMF patients, and possible associations with FMF pathogenesis. Sixty FMF patients during an attack-free period and 51 healthy children as the control group were included in our study. PON1 Q/R192 and GPX1 Pro197Leu gene polymorphisms were assayed. Blood urea nitrogen, creatinine and serum lipid profile were also measured. PON1 Q/R192 genotype distribution was 52% QQ, 46% QR and 2% RR in the FMF group and 45% QQ, 45% QR and 10% RR in the control group (P > Familial Mediterranean fever 0.05). GPX1 Pro197Leu genotype distribution was 28% PP, 57% PL, 15% LL in the FMF group and 18% PP, 53% PL, 29% LL in the control group (P > 0.05). Blood urea nitrogen, serum creatinine, lipid levels, and the distribution of PON1 Q/R192 and GPX1 Pro197Leu genotypes were similar in the two groups. We conclude that the PON1 Q/R192 and GPX1 Pro197Leu gene polymorphisms are not important risk factors in the development of FMF. However, larger studies are warranted to validate these conclusions.