Percutaneous transcatheter embolization of the arterial duct, using new detachable coils, was performed in 19 patients aged from two to 16 years. The minimal ductal diameter ranged from 0.5 to 2.7 mm. We used a 5 mm diameter coil, 8 cm in length and/or an 8 mm diameter coil, which was 10 cm in length. The coil was connected to a delivery wire with a screw system, and could be detached by rotation of the delivery wire. The coil was straightened by inserting a mandril, with loops then being formed by withdrawal of the mandril. In all patients, the coil was advanced retrogradely and either one or two coils were successfully implanted. Implantation was performed in four patients without the catheter entering the pulmonary trunk across the arterial duct. The ductal ampulla was either absent or very small in five patients, so we implanted a coil which had been cut short. Angiography revealed no residual shunting in 14 patients (74%) and trace residual shunting in five patients. Migration of the coils to the pulmonary arteries, or to a systemic artery, did not occur in any patient. Follow-up using Doppler color flow imaging showed complete closure of the arterial duct in all patients (100%), and no turbulence either in the left pulmonary artery or in the descending aorta in any patient. The use of the new detachable coil may improve the accuracy of placement of the device and reduce the incidence of its migration.