We have investigated the frequencies of HLA-B*44 alleles and their haplotypic associations with HLA-A, -C, and -DRB1 loci in 450 healthy unrelated Koreans, including 213 parents from 107 families. All 79 samples (17.6%) typed as B44 by serology were analyzed for B*44 alleles using polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) method. A total of three different B*44 alleles were detected: B*44031 (allele frequency 4.7%), B*44032 (3.1%), and B*4402 (1.3%). Three characteristic haplotypes revealing strong linkage disequilibrium were A*3303-Cw*1403-B*44031-DRB1*1302 (3.6%), A*3303-Cw*07-B*44032-DRB1*0701 (2.8%), and A*3201-Cw*05-B*4402-DRB1*0405 (0.4%). In addition, a strong association was observed for B*4402 with A*0301. The B*4403-bearing haplotypes of Koreans appear to be relatively common in Asian populations, whereas the B*4402-bearing haplotypes share some similarity to those of Caucasians. HLA-B44 alleles demonstrate a limited allelic diversity and comprise distinctive extended haplotypes in the Korean population. It is suggested that the frequencies of B44 subtype mismatches among ABDRB1-matched unrelated donor-recipient pairs would be low in this population.