On the basis of data collected during the 12th International Histocompatibility Workshop, we postulated a possible linkage disequilibrium between the TAP1C allele and the DRB1*1104-DQA1*0103-DQB1*0603 haplotype characteristic of Ashkenazi Jews. In order to confirm and extend this preliminary observation, a group of 34 subjects carrying this haplotype was analysed for TAP1 and TAP2 polymorphisms and compared with two control groups sharing either the DRB1 or the DQA1 and DQB1 alleles with the test group. The TAP1*0301 and TAP2D alleles were found to be strongly associated with the entire haplotype, but not with the DRB1*1104 or the DQA1*0103-DQB1*0603 alleles when carried separately. These data show a strong linkage disequilibrium of TAP1*0301 and TAP2D alleles with the DRB1*1104-DQA1*0103-DQB1*0603 haplotype of Ashkenazi Jews, extended on the centromeric and telomeric side to the DPB1*0201 and A1-B35 alleles, respectively.