ABSTRACT. Objective. Kawasaki disease (KD) is the most common acquired heart disease in children worldwide. The incidence of KD varies among different countries, with Asian countries supposedly having higher incidences than Western countries. However, the incidence of KD in Taiwan has not been well investigated.Methods. Since the implementation of Taiwan's National Health Insurance (NHI) in 1995, NHI has covered health care for >96% its population. Using the NHI database from 1996 to 2002, we investigated epidemiologic features of KD (International Classification of Diseases, Ninth Revision, code 446.1), the rate of coronary artery aneurysm formation (International Classification of Diseases, Ninth Revision, code 414.11), and the change in incidence during the recent 7 years. We also compared the annual incidences in Taiwan with those reported by other countries.Results. During the 7-year study period, KD occurred most frequently in the summer and least frequently in winter. It is interesting that the highest peak occurred in the summer of 1998 at the same time that Taiwan's enterovirus 71 epidemic was occurring. Ninety-one percent of KD cases occurred in children who were <5 years old, and the male-to-female ratio was 1.70:1. Recurrence of KD was found in 1.3% (94 of 7305) of these children, and coronary artery aneurysm was found in 7.3% (536 of 7305). The annual incidence per 100 000 children was 146 in children <1 year old, 98 in 1-year-old children, 51 in 2-year-old children, 28 in 3-year-old children, 19 in 4-year-old children, and 5.3 in 5-to 9-year-old children; the incidence of KD decreased with increased age. The overall incidence was 66 cases per 100 000 children <5 years old from 1996 to 2002 with the annual incidence not differing significantly during the 7-year study period.Conclusions. KD in Taiwan occurs more frequently in boys and in the summer months. During the 7-year study period, the annual KD incidence in Taiwan of 66/100000 in children <5 years old was the second highest in the world after Japan. Kawasaki,1 it is now the most common cause of acquired heart disease in children in the developed world. Although usually self-limiting, KD is associated with a range of complications, the most important being the development of life-threatening coronary artery abnormalities.Reported incidences of KD in different countries vary widely. For example, Japan has the highest annual incidence in the world. It reported 100 to 110 KD cases per 100 000 children Ͻ5 years old between 1995 and 1998 but with ϳ200 cases per 100 000 in times of epidemic. [2][3][4][5] Beijing reported annual citywide incidence of 18.2 to 30.6 per 100 000 from 1995 to 1999, 6 and Hong Kong reported an annual incidence of 25.4 per 100 000 from 1989 to 1994 and 32 from 1994 to 2000. 7,8 Among the annual incidences reported for Western countries, the United States reported 17.6 and 17.1 cases per 100 000 children Ͻ5 years old in 1997 and 2000, respectively, 9 and from 1996 to 1999, the United Kingdom reported 5.5 per 100 000 childre...