The prevalence of valvular heart disease (VHD) in the United States was estimated to be approximately 2.5% in the 1990s. The prevalence currently is thought to be increasing because of more accurate diagnostic methods and aging of the population. Mitral regurgitation (MR) is the most common valve defect, followed by aortic stenosis (AS) and aortic regurgitation (AR). Degenerative disease is the most common etiology of MR, AS, and AR, though these forms of VHD also can be caused by congenital valve defects, systemic inflammatory diseases, endocarditis, and many other conditions. Mitral stenosis, most often caused by rheumatic fever, is uncommon in the United States. When VHD is suspected, transthoracic echocardiography should be obtained first. Other tests, including transesophageal echocardiography, computed tomography scan, magnetic resonance imaging study, and cardiac catheterization, are used in special situations to obtain more detailed diagnostic information. Guidelines for VHD management recommend interval monitoring with echocardiography. The exact interval recommended depends on the severity of the valve dysfunction and whether the patient is symptomatic. Monitoring of asymptomatic patients is important because early intervention, when valve function worsens or symptoms develop, is associated with better outcomes.