Williams-Beuren syndrome is a rare genetic malformation with predilection for supravalvular aortic stenosis. Apart from cardiovascular malformation, hypocalcemia, developmental delay, and elfin facies, challenging airway make perioperative management more eventful. Association of infective endocarditis within the aortic arch and pseudoaneurysm formation is infrequent. We, hereby report a case of pseudoaneurysm formation and infective vegetation within the aortic arch in a patient with Williams syndrome and the role of transthoracic echocardiography in its perioperative management.