Introduction: Although thrombolytic administration is inevitable in the management of massive pulmonary embolism, contradictions exist in the treatment of sub-massive pulmonary embolism. There are drawbacks to thrombolytic treatment due to potential serious side effects such as cranial hemorrhage. Case Report: An 84-year-old female patient was admitted to the emergency service because of pain and lack of a pulse in her right arm and %61 oxygen saturation without any respiratory system complaints. A computerized tomography showed pulmonary embolism close to totality in the bilateral main pulmonary arteries and peripheral embolism in the right brachial artery. We considered a sub-massive pulmonary embolism in this patient with no hypotension despite bilateral pulmonary artery embolism, good general condition, but a dilated right ventriculi in transthoracic echocardiography. Since the PESI score was 115, it was decided that the patient was in the high-risk group. After administration of 100 mg Alteplase as thrombolytic therapy, her oxygen saturation increased to 95% in the room air and her complaint of right arm completely regressed. Furthermore, none of the possible complications from thrombolytic therapy, such as fatal bleeding, were observed in our patient. Conclusion: In this article, it is emphasized that thrombolytic therapy is an appropriate choice for patients with sub-massive pulmonary embolism and acute arterial embolism.