Thirty patients with peripheral arterial embolism underwent conventional transthoracic echocardiography. Transoesophageal echocardiography was also performed in ten of the same patients. The detection rate of cardiac abnormalities considered responsible for embolism was five of 20 in patients who received only transthoracic echocardiography and eight of ten in those who underwent transoesophageal echocardiography. One abnormality was detected by transthoracic echocardiography in the ten patients who received both tests, while eight cardiac or aortic abnormalities were discovered by transoesophageal echocardiography (P < 0.05). Transoesophageal echocardiography is significantly better than conventional transthoracic echocardiography at detecting cardiac sources of peripheral arterial embolism.