PURPOSE: Febrile seizure(FS) is one of the most common neurological conditions during childhood, but the pathogenesis of FS remains ambiguous. Various studies have shown that brain-derived neurotrophic factor(BDNF) increased neuronal excitability. In this study, to determine whether the polymorphisms of SNP 6265 within the gene encoding BDNF are associated with susceptibility to FS, the frequencies of the polymorphisms were investigated in children with FS and control subjects. In addition, we analyzed the SNP 6265 polymorphisms in Generalized epilepsy with febrile seizures plus (GEFS+) that hasn't been studied as yet in Korea. METHODS: A total of 79 children selected throughout a collaborative study of Catholic Child Neurology Research Group were divided into three groups: (1) FS(n=30); (2) GEFS+ (n=19); (3) control subjects(n=30). Genotypes and allelic frequencies for the polymorphisms of SNP 6265 located at nucleotide 196 was analyzed and compared among the groups. RESULTS: In this study, proportions for A homozygote, A/G heterozygote and G homozygote for BDNF were as follows: in FS, 46.7%, 36.7% and 16.7%, in GEFS+, 26.3%, 47.4% and 26.3% and in control subjects, 60.0%, 16.7% and 23.3%. The allele A and G frequencies for BDNF in FS were 65.0% and 35.0%, in GEFS+ were 50% and 50%, and in control subjects were 68.3% and 31.7%. However, these differences in genotype proportions and allele frequencies among three groups were not significant. CONCLUSION: These results suggest that genomic variations of BDNF might not be the susceptibility factor for FS and GEFS+ in Korean population.