Residual atrial septal defect (ASD) is a rare complication after percutaneous closure of an ostium secundum atrial defect in eligible patients. Cardiac imaging, mainly transthoracic and transesophageal echocardiography is essential to establish the diagnosis. Surgical closure is the therapeutic strategy of choice. We present the case of a 54-year-old woman who presented with a residual left-to-right atrial shunt four years after percutaneous closure of an ASD ostium secundum.