The association of HLA-A and -B antigens with Bf alleles was investigated in 200 parents from 100 unrelated families. There were significant associations between HLA-A3 and Bf-F, B7 and Bf-S, B8 and Bf-S, B12 and Bf-F, and BW 35 and Bf-F. Three-point HLA-A,B,Bf haplotype frequencies, linkage disequilibrium parameters, and chi-square values were determined both from the genotype and from the phenotype data. Although the HLA-B,Bf associations involve antigens that are also present in the highly associated A,B and B,D haplotypes of the Caucasian population, there was--with the possible exception of HLA-A3,B7,Bf-S--no significant three-point association for HLA-A,B,Bf.