The administration of i.v. gamma globulin (IVGG) for Kawasaki disease was investigated throughout Japan in 1993 by obtaining information from the pediatric departments of 2652 hospitals with more than 100 beds. A total of 1826 hospitals (68.9%) responded, reporting on 11,221 patients who were diagnosed during the survey period from January 1991 to December 1992. There were 8958 patients (79.8%) who received IVGG treatment. The most common treatment modality was 200 mg/kg (29.6%), followed by 400 mg/kg (18.7%) and 300 mg/kg (12.9%), all for 5 days. The distributions of total dose were: 1000 mg/kg or less, 45.7%; 1001-1500 mg/kg, 27.3%; and over 1500 mg/kg, 23.8%. For all patients to whom IVGG was administered, treatment was started in 53.8% by day 5 of illness and in 86.1% by day 7. The proportion of those with cardiac sequelae was higher in patients who were treated with IVGG, possibly due to the fact that those who were more severely affected were more likely to be treated with IVGG.