Diagnostic reliability of percutaneous parietal pleural biopsy with use of the Abrams needle technique performed over a period 1989-1994 was assessed in 37 patients with pleural effusion of unknown etiology, aged 24-82 years. Adequate diagnostic specimens were obtained in 33 patients. Histopathological diagnosis established neoplasma (39,4%), tuberculosis (9.1%) and chronic nonspecific pleuritis (51,5%). No complications of the procedure were encountered. Pleural needle biopsy should be more widely applied as a basic method in the diagnosis of pleural effusions of unknown etiology.