Background: Multiple perforations in the floor of the oval fossa may be an obstacle for transcatheter closure. Thus, we analyzed the interventions in 33 patients with more than one interatrial communication in comparison with 370 procedures with a single defect. Methods and Results: A diagnostic catheterization, which included a balloon-sizing maneuver, was performed. We implanted a total of 46 occluders, made up of 42 Amplatzers and 4 CardioSEALs. In 20 patients, the defects were closed with a single occluder, namely 18 Amplatzer and 2 CardioSEAL devices. Complete closure was achieved in 15 patients, while a tiny residual shunt remained in 5 patients. In 13 patients, two devices were implanted, without any residual shunt being found immediately after implantation. In 3 patients, the occluders did not touch each other. In 10 patients, their rims overlapped. In comparison with the control group, the group with multiple defects did not differ in the distribution of age, gender, and indications for device closure. The mean time of the procedure, and the time required for fluoroscopy, however, were significant longer (P< 0.001). These times ranged from 45 to 250 minutes with a median of 140 minutes, and from 0.0 to 39.2 minutes, with a median of 12.0 minutes, respectively. Also, the association with an atrial septal aneurysm was significantly more frequent 61 vs. 17%; P< 0.001). The times taken during insertion of double devices were also significantly longer than those needed for insertion of a single device (P< 0.001). Conclusions: Transcatheter closure of multiple defects within the oval fossa is feasible with currently available occluders, albeit than, in selected cases it is necessary to implant two devices.