We report a case of early bioprosthetic valve calcification in a 76 year-old woman who had received supplementation with alfacalcidol, an analogue of vitamin D, for 3 years after her initial valve replacement. She underwent aortic valve replacement at the age of 71 and subsequently complained of shortness of breath. Ultrasonic cardiography revealed severe aortic stenosis and we performed a second aortic valve replacement with a bioprosthesis. Histopathologic and x-ray examination showed calcification on the explanted valve. She had not presented with any known risk for early bioprosthetic calcification, suggesting that vitamin D supplementation may accelerate calcification of bioprosthetic valves.