SummaryThoracoscopywasperformedin 76 patients with chronic pleural effusions in which thoracocentesis and blind needle biopsy failed to reach a precise diagnosis.Analysisof thoracoscopic biopsiesprovided adefinitive diagnosis in 53 of the 76 subjects. The diagnoses’“eluded 35malignantdiseases in which the macroscopic appearance was diagnostic inonly27 Patients. Among these 76 patients, a talc poudrage was Performed in the management of recurrent effusion in 33 patients. No recurrence of pleural effusion was observed after 1 month in 87% and after 6 months in 76% of patients with recurrent pleural effusion. We confirm that thoracoscopy is a safe and useful technique forthe diagnosis of pleural effusion which substantially decreasesthe necessity for diagnostic thoracotomy and thattalc poudrage is effective to achieve pleurodesis.