Kawasaki syndrome is an acute self-limited illness of young children that may result in significant cardiovascular sequelae in 20% of patients. The etiology is unknown, but clinical and epidemiologic features strongly suggest an infectious etiology. The incidence of coronary artery abnormalities has been dramatically reduced by administration of intravenous gamma-globulin in the acute phase of illness. This paper reviews the clinical, laboratory, etiologic, epidemiologic, cardiovascular, pathologic, and therapeutic aspects of Kawasaki syndrome. Discovery of the etiology of this disorder will enable more specific diagnostic tests and therapies to be developed.