Aim. To study the distribution of HLA-А*-B*-C*-DRB1*-DQB1* haplotypes in patients with blood system diseases, to establish the most common HLA haplotypes, and to compare the findings with the data on the frequency and distribution of the highest-frequency HLA haplotypes in donors of a number of leading registries. Subjects and methods. In 2008-2012, the Hematology Research Center, Ministry of Health of the Russian Federation, examined 203 patients with blood system diseases who needed allogeneic hematopoietic stem cell transplantation (allo-HSCT) and their 386 blood relatives. Typing ascertained the kind of HLA haplotype in all the patients. Among the patients, there were 97 men who were aged 17 to 64 years (median 38 years) and 106 women who were aged 18 to 59 years (median 40 years). Results. The examinees were found to have 265 different HLA haplotypes. There were 21 high-frequency HLA haplotypes; of them 7 belonged to 10 HLA haplotypes that are most frequent in the representatives of the Caucasoid race. Nearly 30% of the patients who needed allo-HSCT and had no HLA-identical siblings had HLA haplotypes out of the 10 ones that are most common in the representatives of the Caucasoids and thus could expect to find a compatible unrelated donor for a short time. The examinees were found to have a wide variety of HLA haplotypes (265 types in 203 persons). This variety, as well as the extreme polymorphism of HLA alleles, shows that there should be large registries of HLA-typed bone marrow donors in the country. These registries increase the chance to find a HLA-compatible unrelated donor for a short time for a patient with blood disease who has an indication for hematopoietic stem cell transplantation. The performed study supported that there were regional features in the distribution of HLA haplotypes within the same ethnic group. Conclusion. The chance to find a HLA-compatible donor for Russian patients in the large national registry that accumulates donors from different regional populations is substantially higher than that in the foreign registries. To create large cohorts of HLA-typic bone marrow donors from different regions of the country will substantially increase the chance of patients with blood system diseases to find a HLA-compatible unrelated donor.