Abstract: We have reported a 100% association of ocular type of BD with B5 cluster antigens. The HLA results of non ocular type shows respectively 30% and 40% of association with B5 and B5 cluster antigens. These results indicate that B5 cluster antigens are decreased in non ocular patients compared to 62% of normal population. Considering the etiologic fraction for B5 cluster in ocular type patients which was at its maximum level (EF=1); and on the other hand results of the present study shows no association of B5 cluster with non ocular type of BD. Therefore we suggest that B5 cluster antigens has an important role in pathogenesis of ocular lesions and Behcet's patients who are B5 cluster positive, are at a higher risk to develop ocular lesions.