PURPOSE: We evaluated the effects of intravenous immunoglobulin(IVIG) on the levels of laboratory indices examined serially according to the responsiveness to IVIG therapy in children with Kawasaki disease(KD). METHODS: Children with KD(n=63) who had been treated with IVIG at a dosage of 2.0 g/kg were classified into two groups: the IVIG-resistant(consistent fever over 48 hours after initiation of IVIG infusion, n=9) and the IVIG-responsive(defervescence within 48 hours, n=54). The levels of various laboratory indices were determined three times during admission: before, 24 hours after and seven days after IVIG administration. RESULTS: Among the nine children in the IVIG-resistant group, four(44.4% vs 9.3% in IVIG-responsive group, P=0.019) had coronary artery lesions(CAL). On comparing the two groups, the following statistically significant differences(P<0.05) in the levels of laboratory parameters were found in the IVIG-resistant group relative to the IVIG-responsive group:C-reactive protein(CRP) level was higher(19.0 mg/dL vs 10.9 mg/dL), but the platelet count, total protein, and total cholesterol levels were lower before IVIG infusion; the white blood cell(WBC) and neutrophil counts, and the CRP level were higher, but the platelet count was lower 24 hours after IVIG administration; WBC and neutrophil counts, and the CRP and erythrocyte sedimentation rate levels were higher, but hemoglobin and albumin levels were lower seven days after IVIG administration. CONCLUSION: Approximately 15% of patients with KD did not respond to single dose IVIG treatment (2.0 g/kg). IVIG-resistant patients have a higher risk of CAL and seem to be predicted from high CRP levels(>16 mg/dL) before IVIG treatment and persistently elevated levels of CRP(>11 mg/ dL), WBC(>12,000/mm3) and neutrophil counts(>6,500/mm3) 24 hours after IVIG administration.