Infective endocarditis is a rare complication of atrial septal defect closure using transcatheter procedure. We report about infective endocarditis in an 8-year-old boy 3 months after transcatheter closure using a Figulla Flex II atrial septal defect occluder. Transesophageal echocardiography showed vegetation attached to the left atrium side of the device. Device removal and atrial septal defect closure were performed. The device was less endothelialized on the left than on the right atrium side. Therefore, insufficient endothelialization may cause infective endocarditis.