Missense mutations in the gamma2 subunit of gamma-aminobutyric acid (GABA) receptor gene have recently been described in families with idiopathic generalized epilepsies. This study aimed to evaluate whether polymorphisms of the gamma2 subunit of the GABA receptor gene are associated with idiopathic generalized epilepsies. A total of 77 children with idiopathic generalized epilepsies and 83 normal control subjects were included in the study. Polymerase chain reaction was used to identify the C/T and A/G polymorphisms of the gamma2 subunit of the GABA receptor gene on chromosome 5q33. Genotypes and allelic frequencies in both groups were compared. The gamma2 subunit of the GABA receptor (nucleotide position 3145 in intron G-> A) gene in both groups was not significantly different. In contrast, the gamma2 subunit of GABA receptor (SNP211037)-C allele frequency in patients with idiopathic generalized epilepsies was significantly higher than that in healthy control subjects (P = 0.002). The odds ratio for developing idiopathic generalized epilepsies in individuals with the gamma2 subunit of the GABA receptor (SNP211037)-C/C genotype was 3.61 compared with individuals with the gamma2 subunit of the GABA receptor (SNP211037)-T/T genotype. These data suggest that the gamma2 subunit of the GABA receptor gene might be one of the susceptibility factors for idiopathic generalized epilepsies.