Kawasaki disease is now the leading cause of acquired heart disease in childhood, but its long-term prognosis is still unknown. In this study from Japan, 6576 children with Kawasaki disease were followed for a mean time of 12.6 years. Cardiac sequelae occurred in 15.3% of patients. There was an increased mortality during the acute phase of the illness, but overall, the standardized mortality ratio was not elevated following the acute phase. Only among males with cardiac sequelae was there an increased risk of death during the postacute, follow-up period. For the vast majority of patients with Kawasaki disease who do not have cardiac sequelae, there does not seem to be a later increased risk of death.