Bacterial meningitis (BM) is a common central nervous system inflammatory disease. BM may cause serious complications, and early diagnosis is essential to improve the prognosis of affected patients.A 37-year-old man was hospitalized with purulent meningitis because of worsening headache for 12 h, accompanied by vomiting, fever, and rhinorrhea. Head computed tomography showed a lesion in the left frontal lobe. Infectious disease screening showed positivity for hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B core antigen. Cerebrospinal fluid (CSF) leak was suspected based on clinical history. Streptococcus pneumoniae (S. pneumoniae) was detected in CSF by metagenomic next-generation sequencing (mNGS) technology, confirming the diagnosis of purulent BM. After treatment, multiplex PCR indicated the presence of hepatitis B virus (HBV) DNA and absence of S. pneumoniae DNA in CSF samples.We report a rare case of HBV in the CSF of a patient with purulent BM. Multiplex PCR is more sensitive than mNGS for detecting HBV DNA.©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.