Although Kawasaki disease is often self-limiting, significant cardiovascular sequelae may occur in the acute or late stage. The most common late complication is persistent coronary artery aneurysm, which can lead to myocardial ischaemia and even myocardial infarction. We report a case of coronary artery bypass grafting in a 16-year-old boy with a history of undiagnosed Kawasaki disease. Increased awareness of Kawasaki disease, especially among children between the ages of 6 months and 5 years, can increase early treatment and prevent serious complications that may occur in the future.