Aim. The objective of the present study was to elucidate the quantitative characteristics of bone marrow lymphocyte from the children presenting with punctate sarcomas and compare the results thus obtained with the analogous characteristics of such cells from healthy subjects with special reference to the known risk factors of these tumours. Materials and methods. The study included 34 children at the age from 1 to 16 years presenting either with punctate sarcomas or with rhabdosarcomas. The control group was comprised of 15 children. Monoclonal antibodies were used to stain lymphoid cells from bone marrow (the three-color fluorescence technique). Results. The number of T-cytotoxic cells (CD3 +, CD8 +) and NK-cells (CD56 + CD3 -) in the patients presenting with Ewing's sarcoma was significantly greater than in the healthy subjects and in the patients with rhabdosarcoma. In contrast, the number of CD4 + helper-cells in the patients with Ewing's sarcoma was smaller than normal. The patients with rhabdosarcoma were characterized by the markedly elevated number of TCRγ/δ T-cells as compared with the healthy children. It was shown that the subpopulations of T-cells (Leu8), natural killers, and TCRγ/δ cells play an important role in the processes of lymphogenic and hematogenic metastasis in the children presenting with rhabdosarcoma. The low content of TCRγ/δ cells in the children with Ewing's sarcoma may be related to the unfavourable localization of the tumours while the small number of activated T-cytotoxic cells correlates with the large volume of the tumours or the extensive lesion in long tubular bones. It is concluded that the results of the present study provide a basis for the further evaluation of the possibility to use anti-tumour immune preparations for the treatment of punctate sarcomas in the children.