Associations between alleles at the DPA1 and DPB1 loci were analyzed in 181 Norwegian caucasoids. Associations were observed between the DPA1*0201 and the DPB1*0101, *0901, *1001 and *1101 alleles. An association between DPA1*0201 and the DPB1*0901 allele was also observed among 23 healthy Japanese and 24 Japanese MS patients. In addition, it appeared that among Japanese the DPA1*0201 allele may be associated to the DPB1*0501. In conclusion, alleles at the DPA1 and DPB1 loci display different associations among Norwegian caucasoids and Japanese.