The management of fetal heterotopic tachycardias is reviewed from a cooperative study involving 23 cases treated by French Pediatric Cardiology Centers at Angers, Brest, Nantes, Rennes and Tours. There were 17 cases of supraventricular tachycardia (SVT), 5 of flutter and 1 of atrial tachycardia. Seventeen mothers were given an antiarrythmic treatment. They all received Digoxin by mouth, with either Propranolol in 2 cases, Sotalol and Verapamil in one case each. In 5 cases 2 or more other drugs were associated. There was a good in utero response in 12 cases. Among the 23 patients, 5 died, all with hydrops fetalis at the time of diagnosis of SVT. Finally 2 newborns were successfully treated at the time of delivery by a direct puncture of the umbilical cord.