A 43-year-old man had severe aortic stenosis and Maroteaux-Lamy syndrome (mucopolysaccharidosis, type VI). Aortic-valve replacement gave a good long-term result. Information was obtained indicating that his two brothers had also had mucopolysaccharidosis and aortic stenosis and that both had died of cardiac disease. This paper reviews the literature on cardiac involvement in mucopolysaccharidosis.