Polymorphisms outside exon 2 of the DRB1 coding region exhibit increased ambiguities in allele assignments in typing laboratories analyzing the exon 2 sequence alone. This study investigated the frequencies of alleles in DRB1*120101/1206/1210 and DRB1*140101/1454 groups by DNA sequencing of exons 1 and/or 3 and examined their associations with class II alleles at adjacent loci in Koreans. Of 103 individuals, 97 were DRB1*120101 and 6 were DRB1*1210. None carried DRB1*1206, an allele initially characterized from a Korean individual. Association of DRB1*120101 with various DRB3, DQA1, and DQB1 alleles was reflected in 11 different four-locus haplotypes. In contrast, DRB1*1210 was exclusively associated with DRB3*020201, DQA1*0505, and DQB1*0301. All 97 DRB1*140101/1454 samples were DRB1*1454. DRB1*1454 was strongly associated with DRB3*020201, DQA1*010401, and two different DQB1 alleles (*0502, *0503). Continuous updating of HLA high-resolution typing information will be useful in the development of typing and matching strategies for hematopoietic stem cell transplantation.