In order to determine whether pleural drainage with talc instillation was better than pleural drainage alone, in the treatment of malignant effusion, the present trial was initiated. Thirty-one patients with malignant pleural effusion and progressive disease, resistant to conventional therapy, were included. All patients had pleural drainage applied. After re-expansion of the lung, half of the patients had talc instilled through the chest tube. Twenty-one of the 31 treated patients were evaluable. After pleural drainage with talc instillation, all of 9 treated patients obtained complete resolution of the effusion and subjective improvement. After pleural drainage alone, 7 of 12 patients obtained complete resolution of the malignant effusion. If it is possible to re-expand the lung during pleural drainage in patients with a malignant pleural effusion, pleurodesis can be obtained in 60% of the treated patients with pleural drainage alone. This study showed a statistically significant improvement in the treatment associated with instillation of talc into the pleural cavity and this was achieved without causing increased discomfort to the patient.