HLA-A, -B and -DRB1 gene and haplotype frequencies have been calculated from 3892 southern Chinese unrelated cord blood units in a Hong Kong Cord Blood Registry. This is the first large-scale paper to report the distribution of A-B-DRB1 alleles in Hong Kong Chinese Cord Blood Units. This information is important for estimating the optimal and economically cost-effective donor size and likelihood of obtaining appropriately matched cord blood units for Chinese patients awaiting haematopoietic stem cell transplantation. The data are available in the Allele Frequencies Net Database under the population name ‘‘Hong Kong Chinese Cord Blood Registry’’ and the identifier (AFND003358).