In order to investigate the association between IL-1 beta-511 C -> T and IL-1 receptor antagonist intron 2 variable tandem repeat polymorphisms, and febrile seizures in children, 90 children (mean age, 19.7 +/- 11.2 months) diagnosed with febrile seizure and 106 healthy controls (mean age, 14.2 +/- 3.6 months) with no seizure or neurologic events were included in the study. The polymorphisms were analyzed using restriction fragment length polymorphism and agarose gel electrophoresis methods. In the patient group, the frequencies of IL-1 beta genotypes CC, CT, and TT were 24.4%, 52.2%, and 23.3%, respectively, compared with 38.7%, 50.95%, and 10.4%, respectively, in the control group. The TT genotype was significantly more common in the patient group than in the control group (P = 0.044), and the T allele frequency was significantly higher in the patient group (0.50 vs 0.36, P = 0.040). Among the three genotypes (RN1/1, RN1/2, and RN2/2) of the IL receptor antagonist gene variable tandem repeat polymorphisms, the frequency of both the RN2/2 genotype and the RN2 allele were significantly higher in the patient group (P = 0.007). Also RN2 allele frequency was found higher in patient group than controls (0.29 vs 0.15, P = 0.020). IL-1 beta-511 and IL-1 receptor antagonist intron 2 variable tandem repeat polymorphisms may be involved in susceptibility to febrile convulsions in children. (C) 2009 by Elsevier Inc. All rights reserved.