This chapter discusses the application of echocardiography in evaluation of thromboembolic diseases. Echocardiography is indicated in transient ischemic attack (TIA) or cerebral stroke to make or confirm a diagnosis associated with risk of thromboembolism such as mitral stenosis, left atrial dilatation and atrial fibrillation, to detect a direct source of embolism from the heart, and to detect an indirect source of peripheral emboli such as aortic atheroma in the descending thoracic aorta. Not every patient who has had a TIA or stroke needs an echo but it is certainly important in various situations such as abrupt occlusion of a major peripheral or visceral artery, young patient (< 50 years) with cerebral infarction, and strong clinical suspicion of cardiac embolism e. g. recurrent peripheral or cerebral embolic events. Many a time, a cardiac source of embolism is evident on conventional transthoracic echo. A subsequent transoesophageal echo is indicated in the some situations like young patient (< 50 years) with TIA / stroke even in the absence of clinical cardiac abnormalities, older patient ( > 50 years) with no other cause of TIA/stroke, and a normal or inconclusive transthoracic scan with strong clinical suspicion of cardiac embolism.