A 66-year-old woman was diagnosed with severe aortic regurgitation. Blood studies constantly showed positive C-reactive protein. Aortic valve replacement using a mechanical valve was carried out. Four months after the operation, echocardiogram showed aortic regurgitation due to paravalvular leakage. Reoperation was performed using a stentless aortic root bioprosthesis. The pathological specimen from the aortic wall was consistent with giant cell arteritis. The patient was treated with prednisone with dramatic improvement of systemic symptoms.