Several cases of Kawasaki disease (KD) were unresponsive to the initial treatment with intravenous immunoglobulin (IVIG). We retrospectively analyzed all children admitted with KD to determine the occurrence and variables associated with the initial IVIG treatment failure. All patients who fulfilled the criteria for KD and were treated with a single dose (2 g/kg) of IVIG between January 1995 and August 2001 were enrolled. An analysis of the patients who had initially failed to respond to IVIG was performed. A total of 120 patients were enrolled during the study period. There were 68 boys (56.7%). Fourteen patients (11.6%) were found to be unresponsive to initial IVIG treatment. Patients who were anemic (Hb<10 G/DL), had a high neutrophil count (> 75%), a high band count, and low albumin were at risk of failure to respond to a single dose of IVIG. We found no correlation among age, gender, days since starting IVIG treatment, and erythrocyte sedimentation rate (ESR) with failure of the initial IVIG treatment. There were 12 patients (10%) who developed coronary artery aneurysms. The failure of a single dose of IVIG treatment occured in up to 11.6% of our Kawasaki patients. We found that low hemoglobin (<10 G/DL), high neutrophil count (> 75%), high band count, and a low albumin were associated with the requirement for retreatment with a second dose of IVIG.