PURPOSE: Without a specific diagnostic method, the clinical diagnostic criteria for atypical Kawasaki disease is known as the presence of coronary artery changes in a patient who did not meet the already estabilished clinical criteria. With this criteria, we are put into dilemma because atypical Kawasaki disease should exhibit coronary artery disease. So, we demonstrated the rate of coronary artery involvement in atypical Kawasaki disease by another diagnostic criteria. METHODS: This diagnostic criteria for atypical Kawasaki disease is "the clinical symptoms which fulfilled four out of six diagnostic criteria below of typical Kawasaki disease with or without the presence of coronary artery changes, and were inconsistent under a through clinical investigation with any other illness similar to Kawasaki disease." RESULTS: The incidence of coronary artery involvement in atypical Kawasaki disease during the acute phase (analysis of 30 cases who were admitted before the 15th day of illness), on the 30th day of illness (26 cases) and on the 60th day of illness(26 cases) were 20.0% (dilatation : 13.3%, aneurysm : 6.7%), 19.2% (dilatation : 19.2%, aneurysm : 0.0%), 7.7%(dilatation : 7.7%, aneurysm : 0.0%), respectively. CONCLUSOIN: Kawasaki disease may occur in atypical type, ranging over many severe involvements of vital organs including the coronary artery. Up to the present, there are no infallible diagnostic tests for Kawasaki disease and it is advisable to deemphasize the rigid adherence to the current already proposed diagnostic criteria for Kawasaki disease.