It is shown that 2',3'-dideoxy-3'-aminonucleoside 5'-triphosphates with adenine, guanine, cytosine and thymine bases are effective inhibitors of DNA polymerase I, calf thymus DNA polymerase alpha and rat liver DNA polymerase beta. The effect of the above-mentioned compounds is markedly higher than corresponding action of the well-known DNA synthesis inhibitors arabinonucleoside 5'-triphosphates and 2',3'-dideoxynucleoside 5'-triphosphates. 2',3'-dideoxy-3'-aminonucleoside 5'-monophosphate residues incorporate into the 3'-terminus of the primer and terminate the DNA chain elongation. The possibility of using 2',3'-dideoxy-3'-aminonucleoside 5'-triphosphates as terminators for DNA sequencing by the polymerization method is demonstrated.