The etiology of glioma remains unclear so far. Human herpesvirus 6 (HHV-6) might be associated with glioma, but there is no direct evidence to support this. High percentages of HHV-6 DNA and protein were detected in tissue from gliomas, compared with normal brain tissue. In addition, a strain of HHV-6A was isolated from the fluid specimens from glioma cysts. High levels of interleukin 6 (IL-6), interleukin 8 (IL-8), tumor necrosis factor α, and transforming growth factor β (TGF-β) were detected in the cyst fluid specimens from HHV-6-positive patients with glioma. Furthermore, HHV-6A infection promoted IL-6, IL-8, and TGF-β production in astrocyte cultures. Our studies strongly suggest the involvement of HHV-6 infection in the pathogenesis of glioma.