Tuberculosis in children is an important disease because of higher incidence and mortality, especially in developing and underdeveloped countries. The objectives of this study were to evaluate the cause of antituberculosis medication in children and to find out the basic data for proper drug regimen. We reviewed the medical records of 198 patients who had been treated with antituberculosis drugs from Jan. 1991 to Dec. 1993 in Anam Hospital of Korea University Medical Center. The results are as following; 1) Of 198 patients, 69 cases(34.8%) had treated due to BCG complications. They were all medicated with INH. The durations of medication were 3 months in 46 patients(66.7%), 4~6 months in 17 patients(5.8%), 7~9 months in 4 patients(5.8%), 10-12 months in 2 patients(2.9%). 2) Of 198 patients, 68 cases(34.3%) had treated due to chemoprophylaxis, 59 patients (29.8% of all cases) had histories of house hold contact. Of 68 cases, 51 patients (86.4%) were medicated with INH only, 8 patients (13.6%) were medicated with INH and RFP. 3) Other causes of antituberculosis medication were tuberculous lymphadenitis(14.1%), pulmonary tuberculosis(10.6%), meningitis, miliary tuberculosis(2.0%), and pleurisy(2.0%). Most common causes of antituberculosis medications in children were complication of BCG vaccination and chemoprophylaxis after household contact. So early detection of adult tuberculosis and development of convenient diagnostic methods and safe vaccine for childhood tuberculosis is necessary.