AbstractInflammation and genetics may play a role in the pathogenesis of febrile seizures (FSs). We aimed to test whether interleukin‐1β (IL‐1β), IL‐1 receptor antagonist (IL‐1 Ra), IL‐6 promoter, IL‐8, IL‐10, or tumor necrosis factor (TNF) gene polymorphisms could be used as markers of susceptibility to FSs. An association study was performed among a cohort of 104 patients with FSs and 143 normal control subjects. There was no significant difference between patients and controls in the distribution of allele frequencies of the IL‐1β promoter, IL‐1β exon 5, IL‐6 promoter, IL‐8, IL‐10, or TNF‐α gene polymorphisms. In contrast, the IL‐1 Ra‐I homozygote was more frequent in patients with FSs than in healthy controls (93.2% vs. 83.92%, χ2=4.51,P=0.034). In addition, individuals homozygous for the IL‐1 Ra‐I genotype were more than twice as likely to develop FSs than individuals heterozygous for the IL‐1 Ra‐I/II genotype (OR, 2.63, 95% CI: 1.08–6.39; χ2=4.55,P=0.033). We conclude that the IL‐1 Ra gene might be one of the useful markers for predicting susceptibility to FSs. J. Clin. Lab. Anal. 24:154–159, 2010. © 2010 Wiley‐Liss, Inc.