To better determine the risks of transcatheter closure of a patent ductus arteriosus (PDA), a model of PDA was made in newborn piglets by using 5- to 7-mm angioplasty catheters to dilate the probe PDA. This maneuver resulted in a permanent PDA in most piglets. Four to 6 weeks later PDA closure was attempted using the Rashkind PDA occluder. Twelve such procedures were attempted, using clean but nonsterile technique. Nine of 12 PDAs were successfully closed. Two failures were the result of inability to successfully traverse the PDA. This problem was solved by using a long sheath to position the device properly. Four complications occurred, all related to device release: left pulmonary artery embolization in 1 case, femoral artery embolization in 1, torn pulmonic valve cusp in 1 and lodgment of a prosthesis on a pulmonic valve cusp. Two successfully implanted devices were infected at necropsy. This study demonstrates the value of a piglet model in testing transcatheter PDA occlusion devices, the importance of sterile technique in such procedures, the hazards of device retrieval through the right heart and the feasibility of transcatheter PDA closure.