Introduction: Febrile seizures (FS) are the most common neurological disease in childhood. The etiology of FS is the subject of numerous studies including studies regarding genetic predisposition. Aim: The aim of the study was to analyze the association of TRPV1 rs222747 and KCC2 rs2297201 gene polymorphisms with the occurrence of FS. Materials and Methods: The study included 112 patients diagnosed with FS classified as simple febrile seizures (SFS) or complex febrile seizures (CFS). We analyzed selected polymorphisms of KCC2 and TRPV1 genes using the Real-time PCR method. Results: The CT and TT genotypes of the rs2297201 polymorphism of the KCC2 gene are significantly more common in the group of children with FS than the control group (p = .002) as well as the allele T of this polymorphism (p = .045). Additionally, genotypes CT and TT of the rs2297201 polymorphism of the KCC2 gene were more frequent in the group of children with CFS compared to the control group (p < .001). Different genotypes and alleles of the rs222747 TRPV1 gene polymorphism were not associated with the occurrence of febrile seizures or epilepsy, nor were associated with the occurrence of a particular type of febrile seizure (p = .252). Conclusion: These results indicate that the CT and TT genotypes, as well as the T allele of rs2297201 polymorphism of the KCC2 gene, could be a predisposing factor for the FS, as well as the occurrence of CFS.