The patient was a 62-year-old woman with CD5(+) diffuse large B-cell lymphoma. Treatment with the R-CHOP regimen (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) was started. On the eleventh day of the third cycle, headache and low grade fever developed. Her consciousness gradually deteriorated. Seven days after symptom onset, she was brought to the emergency department of our hospital. Cerebrospinal fluid (CSF) analysis revealed a white blood cell count of 25/μl, and a protein level of 188 mg/dl. Antibacterial and antiviral agents were administered based on a diagnosis of acute meningitis. She showed no improvement. We performed another lumbar puncture and intrathecal chemotherapy, a combination of methotrexate and dexamethasone, was administered because we suspected central nervous system involvement of lymphoma. She showed transient improvement. On day 12, we started the R-MPV regimen (rituximab, methotrexate, procarbazine, and vincristine). However, fever and disturbance of consciousness persisted. On day 20, we empirically started anti-tuberculosis treatment. Four days later, tubercle bacilli were confirmed by CSF culture after a 23-day incubation. We ultimately confirmed a diagnosis of tuberculous meningitis. Impaired cellular immunity in lymphoma patients increases the risk of tuberculosis. It is important to consider tuberculous meningitis in the differential diagnosis of a lymphoma patient presenting with meningitis.