A 6-month-old female intact kitten was referred to Cornell University Hospital for Animals for further evaluation of a continuous heart murmur. A grade IV/VI systolic heart murmur was auscultated with a point of maximal intensity (PMI) at the left cranial sternum. Echocardiogram revealed left-sided cardiac enlargement, a possible aberrant vessel with low velocity of flow at the bifurcation of the pulmonary trunk, and evidence of pulmonary hypertension given dilation of the pulmonary arteries and trace tricuspid valve regurgitation. A saline contrast study (bubble study) was negative for right-to-left shunting at the aberrant vessel. A computed tomography (CT) scan confirmed the presence of a large patent ductus arteriosus (PDA). Surgical ligation of the PDA was performed via thoracotomy. One-day post-operative echocardiogram revealed residual flow with a 90% decrease in diameter of the PDA and resolution of pulmonary hypertension. One-month post-operative echocardiogram showed residual flow and normalized left atrial and ventricular size.