Substrate properties of dNTP analogues in the DNA synthesis reaction catalyzed by Thermus aquaticus DNA polymerase were studied. It was shown that most of dNTP analogues which were known as terminators of DNA synthesis of E. coli DNA polymerase I were able to terminate DNA synthesis catalyzed by Thermus aquaticus DNA polymerase. An interesting feature of Thermus aquaticus DNA polymerase was the ability to utilize 3'-azido-2',3'-dideoxythymidine triphosphate as terminating substrate. Relative efficiency of tested dNTP analogues incorporation into the DNA growing chain was estimated.