A total of 34 tissue biopsies were collected from nasopharyngeal carcinoma (NPC) patients and 5 controls with non-NPC. Extracted DNA from tissue biopsies were analyzed for presence of specific gene sequences to EBV type A and type B, and HHV-6 by polymerase chain reaction (PCR). The different sequences of EBV type A and B were parts from the highly divergent forms of the EBV nuclear antigen 2 (EBNA 2). The PCR amplified products for EBNA 2A and EBNA 2B were 115 and 119 base pairs respectively whereas that of HHV-6 DNA was 776 base pairs. The results demonstrated that EBV DNA was detected in 32 of 34 cases (94.1%): 28 (82.3%) with type A, 2 (5.9%) with type B, and 2 (5.9%) with both types. EBV DNA of type A could be detected 1 (20%) of 5 controls. HHV-6 DNA was in 5 of 34 samples (14.7%) whereas HHV-6 DNA was not detectable in biopsy tissues from controls. The results show that in the NPC patient group, A type of EBV is predominant. Detection of HHV-6 DNA in patients group only might be resulted from reactivation of a latent infection or association with EBV-induction of NPC.