Background: Pulmonary embolism (PE) is a common disorder that is associated with significant morbidity and mortality. The primary cause of death in fatal PE is right-sided heart failure. Several randomized, controlled trials comparing thrombolytic therapy with heparin in patients with an acute PE have demonstrated more rapid clot resolution in those treated with thrombolysis. Objective: Study the effectiveness and complications of thrombolytic therapy for massive pulmonary embolism. Patients and Methods: Sixty patients with objectively confirmed massive pulmonary embolism were divided into two equal groups. First group with no contraindication for thrombolytic therapy was treated by (streptokinase or recombinant tissue plasminogen activator) and second group with absolute contraindication for thrombolytic therapy was treated by unfractionated heparin (UFH).  Results: CT pulmonary angiography showed that main pulmonary artery embolism was 25%, bilateral saddle shape pulmonary embolism 41.6%, left pulmonary artery embolism 15% and right pulmonary artery embolism 11.6% , and CT was not done in 4 patients because they were unstable. Mortality was high in patients with main  pulmonary embolism 13.3%. Mortality was 20% in thrombolytic  therapy treated group compared to 50% in heparin treated group and result was statistically significant . Moderate bleeding occurred into left knee in one patient of thrombolytic therapy treated group and mild Hematemesis occurred in one patient of heparin treated group but no mortality occurred due to bleeding. Conclusion: Thrombolytic treatment reduced overall mortality of patients with acute massive PE, and was not associated with major bleeding.