In search for a new sclerosing agent for pleurodesis, fibrin tissue adhesive is compared to tetracycline for its efficacy in rats. Twenty- four albino Wistar rats were divided into 3 groups. Groups 1, 2, and 3 were given intrapleural isotonic saline, 35 mg/ kg tetracycline, and fibrin tissue adhesive with fibrinogen and thrombin concentrations of 30 mg/ mL and 10 U/ mL, respectively. Rats were evaluated for macroscopic pleural adhesions and mean values of macroscopic scoring were compared among the groups. Fibrin tissue adhesive - and tetracycline- treated rats had significantly more adhesions compared to the control group, whereas fibrin tissue adhesive was more effective for pleurodesis than tetracycline and no deaths or major side effects were observed in any rat. Thus, fibrin tissue adhesive was found as a more effective sclerosing agent than tetracycline for pleurodesis in rats.