Development of improved devices for interventional closure of atrial septal defect and patent foramen ovale increased the number of adult patients who are being referred for transcatheter closure. We report two cases that were scheduled for patent foramen ovale closure because of a right-to-left atrial shunt detected at contrast transesophageal echocardiography in another institution and that were found to have pulmonary arteriovenous fistulas. Embolization of pulmonary arteriovenous fistulas was carried out successfully by transcatheter technique.