Using polymerase chain reaction (PCR), a rapid and highly sensitive method was developed for the diagnosis of tuberculous meningitis. The mycobacterium tuberculosis (M. tuberculosis) genome was detected in CSF of 5 of 6 patients with clinically diagnosed tuberculous meningitis, but not present in CSF from 10 patients with other types of meningitis and 10 normal controls. Furthermore, we detected M. tuberculosis in CSF of 2 of 24 patients with clinically possible tuberculous meningitis. This is highly useful method for the rapid diagnosis of tuberculous meningitis over other conventional method.