Effective palliative treatment in malignant pleural effusion can only be carried out when the lung is fully expanded after drainage of effusion. We investigated the efficacy of intrapleural fibrinolytics for lysing fibrin deposits and improving lung reexpansion in patients with malignant pleural effusion. We randomly allocated 47 patients with malignant pleural effusion into 2 groups: a fibrinolytic group of 24 were given 3 cycles of 250,000 U intrapleural streptokinase; the control group of 23 received pleural drainage only. Pleurodesis with 5 mg of talc slurry was performed in all patients who had lung reexpansion after drainage. Patient characteristics, pleural drainage, lung expansion assessed by chest radiography, and pleurodesis outcomes were compared between the 2 groups. Patient characteristics were similar in both groups. Lung reexpansion was adequate for performing talc pleurodesis in 96% of patients in the fibrinolytic group and 74% in the control group. In the fibrinolytic group, the mean volume of daily pleural drainage before streptokinase administration was 425 mL, and it increased significantly to 737 mL after streptokinase infusion. Intrapleural administration of streptokinase is advisable for patients with malignant pleural effusion.