BACKGROUND: Tuberculous pleural effusion is the most common extrapulmonary site of all disease due to Mycobacterium tuberculosis. The diagnosis of tuberculous pleural effusion is most often established by histologic examination of pleural biopsy specimens. This study documents the utility of smear and culture of pleural fluid and pleural biopsy specimens for tubercle bacilli. METHODS: Between March 1998 and August 1999, we performed thoracentesis with or without pleural bio-psies on 148 patients with pleural effusion according to protocol with Abrams needle. Before the pleural biopsy, a diagnostic thoracentesis was performed. Aliquots of pleural fluid (30 mL) were submitted for biochemical, cytologic, and bacteriologic studies, Ziehl-Neelsen staining and culture in Lowenstein-Jensen medium. At least five samples of parietal pleural tissue were obtained, one for mycobacterial study and another for histologic study. RESULTS: Thirty-seven of the 148 patients were proved to have tuberculosis (24 men and 13 women) with a median age of 32 years (range, 21~91). Pleural biopsy was performed on 35 of the 37 patients with tuberculous pleural effusion. Granuloma was present in 33 of the 35 patients investigated with acid-fast bacilli in 9 patients. The smear for acid-fast bacilli of pleural fluid was positive in 1 patient and the culture for M. tuberculosis was positive in 5 of 37 patients. Pleural biopsy culture was positive in 3 of 35 patients. The 2 patients who could not carry out the pleural biopsy were positive in pleural fluid and pleural tissue mycobacterial culture, respectively. CONCLUSION: In our test, Ziehl-Neelsen staining and culture for M. tuberculosis of pleural fluid and pleural specimen gave a higher yield (5.4%) than the histologic methods alone in establishing the diagnosis of tuberculous pleural effusion.