Coronary aneurysm in Kawasaki's disease (Acute febril infantile mucocutaneous lymph node syndrome, MCLS) may cause sudden death in childhood and ischemic heart disease in adults. We encountered two adult autopsy cases of Kawasaki's disease with multiple coronary aneurysms. The first case was a 56-year-old man who hospitalized due to recurrent syncope since 51 years of age. At age 55 coronary angiography (CAG) had shown multiple aneurysms in the left and right coronary artery. In September 1991, he developed chest pain and was brought to the hospital, almost dead on arrival (DOA). The patient died later the same day despite cardiopulmonary resuscitation. Autopsy findings showed cardiomegaly (470 g) with multiple coronary aneurysms of three coronary arteries. Microscopically, intimal thickening and medial thinning were found in the aneurysmal wall with calcification and disruption of the internal elastic lamina. The second case, a 28-year-old man had been diagnosed with rheumatic fever and mitral regurgitation at 4 years of age. Coronary aneurysms were noted on CAG at 26 years of age. In April 1992, he developed fever and was admitted to a local hospital where he was diagnosed with infectious endocarditis. After his being transferred to our hospital, disturbance of consciousness suddenly developed and he died in September 1992. Autopsy findings showed cardiomegaly (430 g) with left ventricular hypertrophy and multiple coronary aneurysms in left anterior descending coronary artery and left circumflex coronary artery. The aneurysmal wall showed intimal thickening and medial thinning with multiple recanalizations of occlusive lumina and fibrous intimal thickening. The mitral valve showed mild fibrosis and calcification without valvular deformity. There was no evidence of bacterial endocarditis. Both cases were finally diagnosed as Kawasaki's disease. Ischemic heart disease or lesions related to coronary aneurysm in Kawasaki's disease may show an increased incidence in the near future. Kawasaki's disease should have been followed even in adulthood after treatment in childhood.