Thoracoscopy was performed in 76 patients with chronic pleural effusions in which thoracocentesis and blind needle biopsy failed to reach a precise diagnosis. Analysis of thoracoscopic biopsies provided a definitive diagnosis in 53 of the 76 subjects. The diagnoses included 35 malignant diseases in which the macroscopic appearance was diagnostic in only 27 patients. Among these 76 patients, a talc dusting 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 for the diagnosis of pleural effusion which substantially decreases the necessity for diagnostic thoracotomy and that talc dusting is effective to achieve pleurodesis.