Detachable balloon devices were applied in the occlusion of experimental ASDs in 20 piglets. The detachable balloons were made from Latex; the occluder balloon was placed on the left atrial side and required a floppy disk and counter-occluder(s) support from the right atrial side (17 experiments), or a second detachable balloon from the right side (3 experiments). Full occlusion was noticed in all cases. There was one device embolization in the descending aorta (device with a regular floppy disk and no counter-occluder). The device was covered by tissue in 3 to 4 weeks with the balloon flat on the septum in approximately 2 months; it required minimal rim and no wires in the left atrium. The double balloon model was wireless. The balloon detachable device was found effective and safe in the occlusion of experimental ASDs in piglets. Cathet. Cardiovasc. Intervent. 51:529 -534, 2000.