Persistent or chronic supraventricular tachycardia is defined as the one occurring in more than 10% of cardiac rhythm during 24 hours. It may begin at any age, persisting months or years, and frequently it is discovered occasionally because it can be asymptomatic. The persistent supraventricular tachycardia (PSVT) represents 20-30% of all supraventricular tachycardias in pediatric age. The two main forms of PSVT are: atrial ectopic tachycardia, and persistent junctional reciprocating tachycardia (PJRT). The authors present 9 cases of children affected by PJRT seen from 1972 to 1985. They discuss the clinical course (mean follow up = 9.5 years), the pharmacologic treatment, the results obtained. They underline the particular resistance to conventional antiarrhythmic therapy of this form. On the other hand an antiarrhythmic treatment is recommended to avoid the risk of congestive heart failure. Nevertheless the prognosis is considered benign because in the majority of cases this type of arrhythmia disappears later on.