Using thermophilic DNA-polymerase from Thermus thermophilus we have amplified by polymerase chain reaction (PCR) specific DNA sequences of Epstein-Barr virus (EBV) and human immunodeficiency virus (HIV). DNA-polymerase from Thermus thermophilus (the molecular mass of 80 to 86 kDa) differs in its physico-chemical properties from DNA-polymerase from the Thermus acquaticus (the molecular mass of 62 to 68 kDa). To amplify the specific EBV DNA sequence oligonucleotide primers for the virus replicon region (oriP-region) were used. As a result of amplification, a specific 405 b.p. DNA fragment was produced. Primers for the virus Gag region were used for amplification of HIV DNA. The possibility to conduct amplification cycles under two temperature conditions was demonstrated.