PURPOSE: To demonstrate genetic background of pathogenesis of Kawasaki disease (KD), I examined the genetic polymorphism of plasminogen activator inhibitor-1 (PAI-1) in KD patients. METHODS: PCR-RFLP of PAI- 1 promotor gene was analyzed in 56 KD patients admitted to Kyunghee University Hospital, Gachon Medical School Gil Hospital, and Eulji Hospital from March to August 2000 and 206 normal control populations. RESULTS: There were no differences in the genotype and allelic frequency of the PAI-1-675 (4G/5G) and PAI-1-844 (G/A) polymorphic site (which are located in the promoter region) between KD and control subjects. Also I could not detect any significant differences in specific genotypes between patients with the coronary artery lesion (CAL) and patients without CAL. CONCLUSION: No association was observed in -844 G/A and -675 4G/5G of PAI-1 gene polymorphism with KD.