This study investigated whether the T-type calcium channel gene CACNA1I causes susceptibility in the Chinese Han population to childhood absence epilepsy, a form of idiopathic generalized seizure disorder. For this investigation, we searched for mutations in the 35 exons and exon-intron boundaries of the CACNA1I gene in 50 Han Chinese patients with childhood absence epilepsy. Seventeen single nucleotide polymorphisms were identified in the 35 exons. Using six single nucleotide polymorphisms as markers, the allele and genotype distributions of all of the identified single nucleotide polymorphisms were examined; there was no significant difference between the childhood absence epilepsy cases and the control groups. Thus, we do not consider the CACNA1I gene to be an important susceptibility gene for childhood absence epilepsy in the Chinese Han population.