Kawasaki syndrome is a fascinating worldwide illness of young children. This acute self-limited vasculitis has become the most common cause of acquired heart disease in children in the United States and Japan. KS causes significant coronary artery disease that may lead to myocardial infarction and sudden death. Clinical and epidemiologic features of KS support an infectious cause, but the etiology remains unknown. Clearly, additional research on the cause of KS and its pathogenesis is needed urgently to allow for improved diagnosis; more specific therapy; and, ultimately, prevention of the disorder.