Kawasaki disease affects children under 4 years of age and is characterized by fever, mucocutaneous rash and cervical lymph node enlargement. It is often complicated by coronary vasculitis and/or pericarditis, myocarditis and endocarditis. Echocardiography is indispensable to diagnose and follow up these complications. A study of the literature and of 4 personal patients showed that it is also useful for the early detection of coronary aneurysm and simple dilatation of the coronary arteries. The sensitivity and specificity of echocardiography in recognizing these complications are such that coronary angiography is exceptionally required. In the search for a cause of prolonged fever in children, the sensitivity of echocardiography makes it possible to diagnose an atypical form of Kawasaki disease.