Behçet's disease (BD) is known to be associated with HLA-B*51, especially HLA-B*5101, in many different ethnic groups. Recently, several HLA-A or -B alleles have been proposed as possible candidate genes for BD in addition to HLA-B*5101. To investigate those associations, we studied HLA-A and -B alleles in Japanese ocular BD patients and the association of possible susceptibility HLA genes with visual prognosis.Eighty-eight Japanese BD patients with uveitis and 104 healthy controls were enrolled for analyses of HLA-A and B alleles. Statistical analysis was performed with Fisher's exact test and odds ratio (OR). Association of the possible susceptible HLA gene and visual prognosis was also examined.The phenotype frequency (PF) of HLA-A*2601 was significantly higher in the patients (37.5%) than the controls (14.4%) (pc=0.00529, OR=3.56), especially in patients without HLA-B*5101 (57.4% vs. 14.1%, pc=4.58x10-6, OR=8.21). In contrast, the PF of HLA-A*2601 was not increased in patients with HLA-B*5101 (14.6% vs. 15.8%). Also, the PF in patients possessing HLA-A*2601 or HLAB* 5101 was increased up to 77.3%. Interestingly, the PF of HLA-A*2601 was significantly associated with poor visual prognosis corresponding to visual acuity of 0.1 or less in the worse eye (p=0.0262).Our results indicate that HLA-A*2601 is possibly associated with ocular BD, independent of HLAB* 5101, indicating that HLA-A*2601 is an additional susceptibility allele candidate of ocular BD in Japan. HLAA* 2601 would also be a possible marker for poor visual prognosis.