Results of the statistical analysis of a nationwide survey of patients with Kawasaki disease diagnosed within a 2-year 6-month period, from July 1982 to December 1984, are as follows. (1) The cumulative number of patients reported by the end of 1984 was 63,399 (36,891 boys and 26,508 girls; male to female ratio 1.4). (2) There were two epidemic years, 1979 and 1982, in which the numbers of patients were more than twofold that of the previous years. (3) A curve plotted for age-specific incidence rate showed a unimodal peak at age 1 year. (4) Steroid therapy was used for 6.3% of the patients, aspirin for 89.8%, antibiotics for 57.6%, and .gamma.-globulin for 11.4%. (5) The proportion of sibling cases was 1.4% and that of recurrent cases was 3.9% of all cases reported. (6) The incidence of cardiac sequelae in 1 month after disease onset was 17.2%.