OBJECTIVE: To study the relationship between anticardiolipin antibodies (ACA) and vascular injury in children with Kawasaki disease (KD). METHODS: Serum ACA-IgG, IgM and IgA were measured qualitatively using ELISA in 55 children with KD. Thirty healthy children served as the controls. RESULTS: In the children with KD, serum ACA-IgG and IgM were found to be positive in 56.4% (31/55) and 23.6% (13/55), respectively. No ACA antibodies were found in the controls ( P <0.01). Severity of clinical manifestations in the children with KD positive or negative for ACA-IgG did not differ. Of the 6 children with KD complicated by coronary thrombus, there were 5 cases of positive ACA-IgG. CONCLUSIONS: ACA-IgG, the most common antibody in children with KD, is correlated to vascular injury, but is not useful in evaluating the severity of KD.