Acute pulmonary embolism (PE) is one of the most common causes of cardiovascular emergency and very high mortality in patients who are hemodynamically unstable. An electrocardiography, bedside transthoracic echocardiogram and computed tomography pulmonary angiogram are usually performed to confirm the diagnosis of PE. A 58-year-old woman with a history of hypertension and smoking complained of dyspnea, chest pain, cold sweating, and general weakness after walking. Firstly; in this case, acute coronary syndrome was considered, aspirin 300 mg and clopidogrel 600 mg were prescribed. The patient underwent coronary angiography; the coronary arteries were free of significant atherosclerotic lesions. After 6 hours of coronary angiograph, shortness of breath was developed, and the patient's clinic was worsened. Electrocardiography and bedside transthoracic echocardiogram findings were highly suspected acute massive PE. The patient was then transferred to Critical Care Unit for monitoring and fibrinolytic therapy was started using the alteplase treatment. The bedside echocardiography provides a safe, rapid, and noninvasive diagnostic tool for evaluation of suspected massive PE.