BACKGROUND: Tuberculous lymphadenitis is the commonest form of extrapulmonary tuberculosis. The laboratory diagnosis of tuberculous lymphadenitis is based on the traditional method of the acid-fast stain and culture of discharge or lymph node. However, acid-fast stain lack sensitivity and specificity, and culture is time- consuming. Polymerase chain reaction is a rapid, sensitive and specific DNA amplification technique for the detection of Mycobacterium tuberculosis in sputum, pleural fluid, cerebrospinal fluid, or others. We evaluate the sensitivity and specificity of the polymerase chain reaction assay for the rapid diagnosis of tuberculous lymphadenitis. METHODS: This study included 50 patient with clinically suspected tuberculous lymphadenitis. We performed fine needle aspiration biopsies (FNAB) on head and neck lymph node. The DNA of the sample was purified by phenol/chloroform method. The nested PCR was performed with TB-CR kit (Bioneer, Korea), which an amplified an insertion sequence IS 6110 sequences. The PCR product was analyzed by agarose gel electrophoresis in the presence of ethidium bromide. RESULTS: Forty-five of the 50 clinically suspected specimens were PCR-positive, five specimens were negative. And one of the 10 negative specimens was positive. The sensitivity and specificity of the PCR was 90% and 90%, respectively. CONCLUSION: The polymerase chain reaction is a very sensitive and rapid method for rapid detection of M. tuberculosis in patients with tuberculous lymphadenitis.