Objectives : Aseptic meningitis is a major cause of Korean childhood morbidity late spring and early summer. However, the nationwide incidences of the disease have not been reported. This study was conducted to evaluate the availability of National Health Insurance data (NHID) for the study of an epidemiological trend in the surveillance of aseptic meningitis in children. Methods : All the claims, under A87, A87.8, and A87.9 by ICD-10, among children below 15 years of age, to the National Health Insurance Corporation, between January and December 1998, were extracted. A survey of the medical record of 3,874 cases from 136 general hospitals was peformed. The availability of the NHID was evaluated by the three following methods: 1) The diagnostic accuracy (the positive Predictive value : proportion of the confirmed aseptic meningitis among the subjects registered as above disease-codes in NHID) was evaluated through a chart review, and according to age, gender, month and region of disease-occurrence. 2) The distribution of confirmed cases was compared with the distribution of total subjects from the NHID, for subjects in General hospitals, or the subjects surveyed. 3) The proportion of confirmed CSF test was confirmed, and the relating factor, which was the difference in CSF-test rate, analyzed. Results : Among 3,874 cases, CSF examinations were peformed on 1,845 (47.6%), and the CSF-test rates were different according to the medical utility (admission vs. OPD visit) and the severity of the symptoms and signs. The diagnostic accuracy for aseptic meningitis, and during the epidemic (May-Aug) and sporadic (Sept-Apr) periods, were 85.0 (1,568/1,845), 86.0 (1,239/l,440) and 81.2% (329/405), respectively. The distributions by age, sex, month or period (epidemic/sporadic) and region, in the confirmed cases, were similar to those in the NHID, in both the subjects at General hospitals and in those surveyed, to within ${pm}7%$. Conclusions : In this paper, the NHID for the subjects registered with an aseptic meningitis disease-code might be available for an epidemiological study on the incidence-estimation of childhood aseptic meningitis, as the NHID could include both the probable and definite cases. On the basis of this result, further studies of time-series and secular trend analyses, using the NHID, will be peformed.