FIELD : medicine.SUBSTANCE : invention relates to medicine. Method for determining markers for the presence of tumor T-lymphoblasts is proposed. PBMC fraction is isolated from the sample of the bone marrow of the patient with acute leukemia, genomic DNA extraction, multiplex polymerase chain reaction using isolated genomic DNA as a template and oligonucleotide primers for TRB loci, electrophoresis, determination of the number of V (D) J-rearrangements associated with tumor clones, the sequencing of eluted multiplex PCR products to determine the sequences of V (D) J-rearrangements of TRB, contained in the major products of multiplex PCR. Established sequences of V (D) J-rearrangements of TRB genes are identified markers of the presence of tumor T-lymphoblasts.EFFECT : invention provides a determination of the type of predominant V (D) J-rearrangements of T cell receptor genes and their number in a diagnostic sample of individual genomic DNA.1 cl, 1 dwg, 1 ex