BACKGROUND: Varicella-zoster virus (VZV) is one of the most common etiologies of aseptic meningitis. The severest manifestation of VZV meningitis is occasionally confused with tuberculous meningitis (TBM). Thus, we investigated the clinical manifestations of VZV meningitis as compared with those of TBM. MATERIALS AND METHODS: All adult patients who were diagnosed with VZV meningitis or TBM were enrolled at a tertiary hospital in Seoul, South Korea, during an 8-year period. The clinical characteristics and cerebrospinal fluid (CSF) profile of patients were analyzed. RESULTS: Seventy-nine patients with VZV meningitis and 24 patients with TBM were enrolled in this study. Of the 79 patients with VZV meningitis, 63 (80%) did not received empirical anti-tuberculous therapy (Group 1) and the remaining 16 (20%) received empirical anti-tuberculous therapy (Group 2), compared with 24 patients with TBM (Group 3). Altered mental status, intensive care unit (ICU) admission, neurologic sequelae, CSF protein levels, and CSF adenosine deaminase levels revealed a trend of being higher in Group 3 than Group 2, which was higher than Group 1. However, the CSF/serum glucose ratio was significantly lower in Group 3 than in Group 1 or Group 2. CONCLUSION: About one fifth of VZV meningitis cases presented as severe manifestations, mimicking TBM. The CSF/serum glucose ratio might be useful to differentiate VZV meningitis from TBM until definite diagnostic tests are available. Physicians should keep in mind that a differential diagnosis between severe VZV meningitis and TBM is needed.