OBJECTIVE To describe the prenatal management and outcome of a series of 66 fetuses with supraventricular tachycardia (SVT). MATERIAL AND METHODS The perinatal data of 66 fetuses with SVT were retrospectively studied from January 1990 to December 2000. Junctional tachycardia was found in 50 fetuses and atrial flutter was found in 16 fetuses. Two groups were studied depending on the absence (n=40) or the presence of hydrops (n=26) at the time of the diagnosis. All fetuses but one were treated prenatally via the mother. Anti-arrhythmic drugs used were: digoxin, sotalol, flecainide or amiodarone. RESULTS Group of fetuses with no hydrops: digoxin was used in 32 cases and allowed 26 fetuses to be converted to sinus rhythm (80%). One intra uterine death (IUD) occurred in this group. Hydropic fetuses group: nine fetuses were converted to sinus rhythm using either flecainide (n=7) or amiodarone (n=2) as first line therapy, whilst digoxin alone or in association with sotalol failed to restore sinus rhythm in all cases. After first line therapy, SVT persisted in 10 fetuses. Nine fetuses received amiodarone alone or in association with digoxin as second line therapy, five of whom were converted to sinus rhythm. Among the 18 alive neonates treated by amiodarone in utero, three presented elevated thyroid stimulating hormone at day 3-4 and required thyroid hormonal substitution therapy for 2-6 months with normal outcome.