Echocardiography is a dominant diagnostic method in cardioembolic and cryptogenic type of ischaemic stroke, which accounts for 15-20 % and 30-40 % of all cases, respectively. The role of echocardiography is to identify sources of embolism. They can be divided into definitive (thrombi, vegetations and tumours) and potential sources. The most common definite source is the thrombus of the left atrial appendage. For most potential sources a strong epidemiological association with stroke is known, but the definite causal relationship was not sufficiently confirmed and there are no generally accepted recommendations for their management in stroke patients. The prevalence of definitive sources of embolism in transesophageal echocardiography (TEE) is 8-20 % in selected populations (cryptogenic stroke or patients without a history or evidence of cardiovascular disease) and in unselected populations up to 23 %. The TEE findings changed the management in 3-39 % of selected populations with ischaemic stroke and in 3-33 % of unselected populations. This high variance points out to considerably diverse approach of various departments to the echocardiographic findings. The contribution of routine transthoracic echocardiography in stroke is limited. The paper outlines an overview of definite and potential sources of embolism.