Recent studies have focused on the possible genetic factor(s) in the pathogenesis of Buerger's disease as well as in Takayasu's disease. We investigated HLA-A, B, C, DR, and DQ antigens in 59 patients with Buerger's disease to confirm statistically significant high frequencies of Aw24, Bw40, Bw54, Cw1, and DR2 antigens and a low frequency of DR9 and DRw52 as compared with those in 152 normal Japanese individuals. As the haplotpye Aw24-Bw54-Cw1-DR4 is known to be common among Japanese, a significantly high frequency of haplotype Bw54-DR2 found in cases of Buerger's disease, instead of that of Bw54-DR4, may suggest a possible cross-linkage occurrence in chromosome 6, which could prove to be an important causative phenomenon in the pathophysiology of Buerger's disease.