The application of molecular biology to human genetics has led to the development of a new field, human molecular genetics. This field has already had a dramatic impact on our understanding of cardiovascular disease and has helped improve diagnosis and treatment of these disorders. We have learned a great deal during the past decade about the long QT syndrome, familial hypertrophic cardiomyopathy, Duchenne muscular dystrophy, hypertension, and supravalvular aortic stenosis. In the coming decade, the pace of discovery will accelerate, offering new opportunities for the prediction and prevention of cardiovascular disease.