During a ten-month period from June 1981 to March 1982 83 patients with Kawasaki syndrome were diagnosed in Finland. The attack rate was 26/100 000 children under five years of age, corresponding to an annual attack rate of 31/100 000 children under five years. The course of the outbreak suggested geographic spreading. 20% of the patients had clinical and ECG evidence of carditis, and ECG abnormalities were found in 59% of the patients. One patient died from a ruptured coronary aneurysm. Neurologic manifestations were seen in 10% of the patients. This is the first reported outbreak of Kawasaki syndrome outside Japan, Korea and the United States of America.