The patent ductus arteriosus (PDA) is a vascular structure connecting the proximal descending aorta to the roof of the main pulmonary artery, near the origin of the left branch pulmonary artery. Transcatheter closure has become the treatment of choice for most cases of PDA in both children and adults; however, measurement of the exact size and morphology of the shunt in adult cases using only contrast fluoroscopy is difficult. We report on a case of a 49-year-old woman who underwent transcatheter closure of PDA with intravascular ultrasound (IVUS) guideance. In the current case, IVUS is feasible and helpful for measuring the exact size and shape of the PDA.