A 20-year-old male patient presented with dyspnea and palpitation. An atrial shunt was detected on transthoracic echocardiography. Transesophageal echocardiography (TEE) showed two secundum atrial septal defects (ASD), 13 mm and 15 mm in size, respectively. There was no other congenital heart disease. During right heart catheterization, pulmonary artery pressure was 40 mmHg and the Qp/Qs ratio was 1.9. His coronary arteries were normal. The patient underwent elective percutaneous ASD closure under general anesthesia and continuous TEE monitoring. The distance between the two defects was 16 mm. Two 25-mm PTS sizing balloon catheters were simultaneously inflated, yielding maximum defect diameters of 13 mm and 15 mm. First the smaller defect, then the larger defect were closed with 15 mm and 18 mm Occlutech Figulla ASD occluders, respectively. Total fluoroscopy time was 25 min, and total procedural time was 95 min. No residual shunt was observed. The patient was discharged the next day without any complication.