Herpes simplex virus, Varicella zoster virus and Human herpes virus-6 caused central nervous system infections and latent infections but there is no data of the 3 viruses being tested from the same cerebrospinal fluid samples with aseptic meningitis or encephalitis in adults patients. These viruses produced similar neurologic symptoms but difficulties existed in differentiating of etiologic agents and therefore the viruses needed to be detected in the early state. Herpes simplex virus encephalitis (HSVE) in adults, if not treated promptly was fatal. If treated with antiviral drugs in the early phase of encephalitis, neurologic sequales decreased by 65%. Recently, a PCR method for detection of HSVE with CSF was developed. VZV primary and secondary infections caused neurologic symptoms of encephalitis or meningitis. The second frequency of adult encephalitis that caused VZV were reported. HHV-6 caused CNS latent infection that was studied with normal adults brains. But there is no data of HSV, VZV and HHV-6 for aseptic meningitis and encephalitis of Korean adults through etiologic study. We cultured CSFs on HEp-2 cells and simultaneously tested for HSV PCR, VZV nested PCR and HHV-6 PCR with 8 specific primers. The PCR results of CSF from meningitis Korean adults were 13/19 (68.4%) for HSV, 10/19 (52.6%) for VZV and 12/19 (63.2%) for HHV-67/19 (36.8%) cases were triple infected HSV PCR, VZV PCR and HHV-6 PCR positive; 3/19 (15.8%) cases were dual infected HSV PCR and HHV-6 PCR positive; 1119 (0.5%) cases was VZV PCR positive. Strong viral DNA amplification of CSF means a causative virus may be present in aseptic meningitis or encephalitis patients and may cause clinical neurologic symptoms. HSV and HHV-6 viruses detection rate were higher than VZV by PCR with CSFs.