Myelodysplastic syndrome is a clonal disease with changes that occur due to mutations that lead to cytogenetic disorders and involve the hematopoietic stem cell. Researchers have shown that colony growth types in leukemic cell culture with acute and chronic myeloid leukaemia are of a prognostic value to determine the likelihood of remission or disease progression. However, there is no single point of view on the prognostic value of clonal culture research methods in MDS. The aim of the study was to determine the role of hematopoietic progenitor cells, the closest descendants of stem cells, in the formation of the pathological process in MDS, and identify the features of colony formation and morphological composition of bone marrow colonies in patients in vitro and in vivo in diffusion chambers implanted in the abdominal cavity of linear animals to determine their possible prognostic value. Bone marrow samples from patients with MDS with an excess of blasts-1 were examined by haematological, cultural, cytological and statistical methods. The features of colony formation in culture with semi-liquid agar of bone marrow of patients with MDS with an excess of blasts-1 were revealed. It has been established that in patients with the disease detection, the colony-forming ability in the semi-liquid agar of progenitor cells is reduced, the number of cells in the colonies decreases, and the appearance of capricious forms of cell aggregates with changes in culture differentiation were detected. The ability of bone marrow in MDS with an excess of blasts-1 to form colony clones by hematopoietic progenitor cells when cultured in semi-liquid agar both in vitro and in vivo was evaluated. Informative indicators of morphofunctional characteristics of stem cells and their descendants in culture, such as colony-forming ability and cell content of colonies, were determined. It is proved that the results of cultivation in diffusion chambers in vivo are comparable with the data obtained in vitro, and can become, along with traditional methods, an additional sign of detection and progression of MDS.