Meningitis is one of the serious complications of extra pulmonary tuberculosis (TB). TB meningitis is the most common chronic meningitis in the world. Early diagnosis and treatment of TB meningitis will decrease the probability of focal neurological defects in these patients. AFB smear and culture are the methods that routinely are used for the diagnosis of tuberculosis. Polymerase Chain Reaction (PCR) of CSF samples is a specific diagnostic technique to approve the TB meningitis infectious. A 26 years old woman with a 10 days history of continuous global headache, nausea and restlessness referred to a neurologist. A brain CT scan without contrast was normal. Then a lumbar puncture (LP) was carried out and CSF sample was analyzed. An aseptic meningitis pattern in the CSF test was observed. All of the other tests were showed to be normal. There was no change in the result of the secondary LP test and CSF analysis that was done less than 24 hours after the first LP. Regarding to the seasonal prevalence of entroviruses, causes of lymphocytic viral meningitis was ruled out. Tuberculin Skin Test (TST) was positive in this patient. The PCR of CSF sample for TB was positive. So the diagnosis of TB meningitis was approved and treatment was started. The patient had a good condition after one year of treatment. Since the TB infectious has a variety of presentations that could be unusual, we should think about TB in patients with similar manifestations of meningitis and pneumonia. Due to its specificity, PCR in these conditions is a very helpful method for TB diagnosis as it can detect few copies of bacilli in biological samples.