Infective endocarditis (IE) is an infection of the endocardial lining of the heart, the heart valves, intracardiac devices or prosthetic valves. The infection is mainly localized on the valvular structures, on the low flow side of the valves or at locations with endocardial damage. In this chapter we will review the epidemiology of infective endocarditis (IE), the Modified Duke criteria for diagnosing IE and understand the role of echocardiography in the diagnosis of IE and complications, demonstrating echocardiograms of cases with native and prosthetic valve infective endocarditis, defining sensitivity and specificity of different imaging modalities in native and prosthetic valve infective endocarditis and describing the diagnostic and prognostic role of imaging findings in IE.