Among Han nationality Chinese and living in the northern area of the Yellow River, 120 patients suffering from Behçet's disease and 100 unrelated healthy individuals were typed for histocompatibility antigens (HLA)-A, -B, -C, and -DR and -DQ antigens. HLA-DR and DQ typing was performed on B-lymphocyte separated with Lympho-B-Kwik. The HLA-antisera were provided by 11th IHWC. Bf alleles and C4 allotypes were determined by immunofixation agarose-gel electrophoresis. HLA-B51 was found in 67/120 (55.83%) patients and in 12/100 (12%) controls, the Chi-square and relative risk values were 45.54 and 9.27, respectively (p < 0.0005). C4AQ0 frequency was significantly increased in the patient group. In the complete form group HLA-B51 was observed more frequently (62.79%). No significant differences of other HLA antigens, frequencies, Bf or B4 alleles were found between the groups.