We report experimental use of a new device for transcatheter closure of atrial septal defects. The device was implanted in surgically created atrial septal defects in two pigs. The devices were easy to implant, and the procedures were short. Both devices were implanted correctly in the desired position, and closed the defect completely. No procedural complications nor problems were encountered. The technique is certainly worth trying in the clinical setting. The device appears to be particularly favourable for use in children because it can be implanted through a 7 French sheath.