IntroductionEnforcement of diagnosis-related group system for appendectomy under the National Health Insurance Service has gradually widened and since July 2013 it has been enforced in all medical institutions in Korea. We have analyzed Health Insurance Review & Assessment Service data to observe changes in claim patterns of pediatric appendectomy during this period. MethodsAll claims data for appendectomy of patients younger than 18 y from 2011 to 2015 were collected. We analyzed the following factors of all cases: age, gender, length of hospital stay, medical cost, method of insurance claim and region. ResultsA total of 112,143 claims were made for appendectomy during the study period. In that, 66,510 (59.3%) were boys and 45,633 (40.7%) were girls. Median length of stay was 5 d and median sum of reimbursement of each claim was 2,198,630 won. Annual number of claims for appendectomy showed a steady decline from 24,888 in 2011 to 19,070 in 2015. Median sum of reimbursement of each claim was 1,862,615, 1,975,500, 2,233,360, 2,376,700, and 2,468,000 won, respectively from 2011 to 2015. Reimbursement for complicated appendectomy increased from 4400 out of 24,888 cases (17.7%) in 2011 to 3865 out of 19,070 cases (20.3%) in 2015. Overall medical cost of all reimbursement for pediatric appendectomy increased from 46,113,202,580 to 47,572,253,300 won. ConclusionsFollowing the universal enforcement of the diagnosis-related group claim system for appendectomy by the National Health Insurance Service, we observed an increase in the median sum of reimbursement per claim and a rise in the rate of claims for complicated appendectomies. These changes were associated with an overall increase in national medical costs.