OBJECTIVE: To determine asthma-related healthcare utilization and costs among children with asthma in Korea. METHODS: We conducted a burden-of-illness study of childhood asthma from the societal perspective. Asthma-related claims in 2003 were extracted from the Korean National Health Insurance claims database. Children (1 to 14 years old) were included in the study if they had two or more medical claims with diagnosis of asthma and prescription for anti-asthma medicines. The total asthma-related cost was the sum of the direct healthcare costs, transportation costs for visits to healthcare providers, and caregivers' opportunity costs for the time spent on hospital or outpatient visits. Direct healthcare costs included the costs of outpatient visits, emergency department (ED) visits, hospital admissions, and pharmaceuticals. RESULTS: A total of 319,714 children with asthma were identified, yielding a one-year asthma prevalence of 3.5%. Asthmatic children had average of 7.82 outpatient visits, 0.02 ED visits, 0.01 admissions, and 0.05 inpatient days per year were recorded. The total cost of insured healthcare services used to treat asthma was $39 million, representing 0.25% of the total expenditure on insured healthcare services in Korea. Outpatient care accounted for 52.6% of the total expenditure on insured services, inpatient care for 2.1%, ED visits for 0.3%, and prescribed medicines for 45.0%. Direct healthcare costs accounted for 84.6%, transportation costs for 8.5%, and time costs for 7.0% of the $66.8 million total cost of treating childhood asthma. CONCLUSIONS: Most of the societal economic burden of childhood asthma was attributable to direct healthcare expenditures, with outpatient visits and medications emerging as the largest component costs. Hospitalizations and ED visits represented a smaller fraction of the cost of childhood asthma in Korea than in other countries. Key words: Asthma, burden of illness, claims data, health care utilization