Background and Purpose— The merits of transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) in the management of transient ischemic attack (TIA) and stroke patients remains matter of debate. Methods— Two hundred and thirty-one consecutive patients with a recent TIA or stroke for which no definite cause and indication for anticoagulation was assessed after standardized work-up underwent TTE and TEE. Echocardiographic findings were categorized into minor and major risk factors. Results— A potential cardiac source of embolism was detected in 55% (127/ 231) of the patients by echocardiography, in 39% (90/231) only identified on TEE. Major risk factors, with an absolute indication for oral anticoagulation, were detected in 20% (46/231) of the patients, in 16% (38/231) of all patients identified on TEE only. A thrombus in the left atrial appendage was the most common major risk factor (38 patients, 16%). The presence of major risk factors was independent of age (χ ² =1.48; P =0.224). The difference in proportions of cardiac sources detected in favor of TEE was highly significant in both patients ≤45 years of age (10/39, P =0.002) and in those >45 years of age (80/192; P <0.004). Conclusions— TEE proved superior to TTE for identification of a cardiac embolic source in patients with TIA or stroke without pre-existent indication or contraindication for anticoagulation. In patients with normal TTE, a cardiac source of embolism was detected by TEE in ≈40% of patients, independent of age. More than 1 of 8 patients of any age with normal TTE revealed a major cardiac risk factor on TEE, in whom anticoagulation is warranted.