Amiodarone treatment in pregnancy might be difficult to handle because of the long half-life of the drug (14-28 days up to 2 months) and because it reduces maternal and neonatal thyroid activity. Although short-term use in pregnancy has been described in cases of fetal supraventricular tachycardia, there are few reports on the chronic use of the drug. In this paper we describe our experience with amiodarone treatment in two pregnant sisters with familial dilatative cardiomyopathy and ventricular malignant extrasystole. Prolonged administration of amiodarone (400-200 mg/die) since the beginning of pregnancy did not have any adverse effects; maternal and neonatal thyroid function was normal, as was the neurological and motor development of the neonates.