PURPOSE: The aim of this study was to identify the predictive factors in the early laboratory findings for cardiac sequelae in Kawasaki disease(KD). METHODES: A retrospective review of the records was conducted of all children with KD who were admitted to the Ulsan Dongkang General Hospital, Masan Samsung Hospital, and Gyeongsang National University Hospital between January 1995 and December 1999. We analyzed and compared the early laboratory findings between the patients with and without coronary artery dilatation. RESULTS: A total of 981 patients were divided into two groups : 826 patients(84.3%) with normal coronary artery and 155 patients(15.7%) with coronary artery dilatation. Age and sex were not significantly different between the two groups. The mean serum C-reactive protein(CRP) in the coronary artery dilatation group and in the normal coronary artery group were 5.0 mg/dl(+/-5.3) and 4.1 mg/dl(+/-5.0), respectively, with a significant difference(P<0.05), whereas the other early laboratory findings had no difference between the groups. CONCLUSION: This study shows that the early serum CRP was higher in patients with KD who had coronary artery dilatation than in those with normal coronary artery. There may be a strong possibility of cardiac sequelae at a high level of serum CRP. However, the cut-off value of serum CRP could not be determined for the prediction of cardiac sequelae in patients with KD.