BACKGROUND: To get the information about the clinical characteristics of the paroxysmal junctional tachycardia in children and to get the general principle in managing these children. METHOD: Analysis of the medical records of the 43 patients(male 30, female 13) with paroxysmal junctional tachycardia(JT) who had been followed-up in this hospital for a mean of 4.6 years(range 1 month up to 12 years) was done. RESULT: In 19 patients, JT started before 1 years of age : in 2, during gestational period, in 15, within 4 months of age, in 2, after 4 months of age. The next peak was 7 in the age of 5 years. The associated cardiac abnormalities were complex congenital defects in 2, tumor in 1, dilated and hypertrophic cardiomyopathy in 1 each. The significant hemodynamic disturbances during JT were noticed in 25. Among those whose surface electrocardiogram during JT were available, mean heart rate during JT was 232rpm(range 160-310) ; narrow QRS complex in 33 and wide in 1 ; P` wave in ST segment or T wave in 22. The delta waves were noticed after stopping JT and during followe up in 20. The types of delta waves were A in 7, B in 9, and indeterminate in 4. The different forms of delta waves unrelated to the degree of fusion were noticed in 6 ; disappearance or intermittent form of delta wave in 4. The efficacy of stopping JT was as follows : ATP 84.4%(38/45), diving reflex 50%(7/14), other vagal stimulation 71.4%(5/7), digoxin 72.7%(8/11), verapamil 54.5%(12/22), D/C cardioversion 62.5%(5/8), neosynephrine 100%(2/2). There were 2 deaths due to associated cardiac defects and 2 elective catheter ablations during the followe up period. The preventive medication with digoxin, beta blocker, and/or verapamil was succesful in 14, partially succesful in 11, failed in 14. The 7 persistent JT were treated with amiodarone in 3, with amiodarone and beta blocker in 1, with flecainide and digoxin in 1. In 1, surgical ablation of accessory pathway was done due to persistent JT. At present, JT do not recur or occur transiently without drugs in 29 ; with drugs, JT become controlled without recurrence in 4, with transient episodes in 4 and with intermittent episodes in 1. CONCLUSION: Althouh the JT in children is benign in most cases spite of the severity during the early period, JT is persistent in cases and needs potent drugs to control JT. Ablation of the foci may be necessary in these cases. Even in patients whose long-term results are benign, it is necessary to choose the optimal drugs to terminate and prevent the JT during the intervening period.