Panic disorder (PD) is an anxiety disorder characterized by panic attacks and anticipatory anxiety. Although a number of association studies have been conducted, no gene has been identified as a susceptibility locus. In this study, we conducted a genome-wide association study of PD in 200 Japanese patients and the same number of controls, using the GeneChip Human Mapping 500 K Array Set. Genotypes were determined using the Bayesian Robust Linear Model with Mahalanobis (BRLMM) genotype calling algorithm. The genotype data were data-cleaned using criteria for SNP call rate (>or=95%), Hardy-Weinberg equilibrium (P>or=0.1%) and minor allele frequency (>or=5%). The significance level of the allele P-value was set at 1.0 x 10(-6), to make false discovery rate (FDR) <0.05. As a result, seven SNPs were significantly associated with PD, which were located in or adjacent to genes including PKP1, PLEKHG1, TMEM16B, CALCOCO1, SDK2 and CLU (or APO-J). Studies with other samples are required to confirm the results.