Abstract Background Werner’s syndrome is an autosomal recessive rare genetic disorder characterized by clinical features suggestive of accelerated aging caused by mutation of the WRN gene. Although some reports exist of aortic valve replacement for aortic stenosis in patients with Werner’s syndrome, case using annular patch enlargement for a small aortic annulus are rare. We report herein the rare case of a patient with Werner’s syndrome and severe aortic stenosis treated by aortic valve replacement with annular patch enlargement. Case presentation A 55-year-old woman genetically diagnosed with Werner’s syndrome suffered from symptomatic severe aortic stenosis with small annulus. Elective aortic valve replacement was performed. Intraoperatively the aortic annulus measured