Echocardiography is a crucial imaging modality for evaluating valvular heart diseases, including mitral valve stenosis and mitral valve regurgitation. It provides comprehensive information on valve anatomy, the underlying etiology, the severity of valve dysfunction, and its hemodynamic impact on the heart and pulmonary circulation. Mitral regurgitation (MR) is the most prevalent valvular heart disease in the United States and the second-most common in Europe. The Carpentier classification is widely used to categorize the mechanisms of MR, aiding in diagnosis and management. The severity of MR is assessed using a multi-parametric approach, as no single parameter is sufficient for accurate grading. Echocardiography, including transesophageal echocardiography when indicated, is essential for detailed evaluation and guiding therapeutic decisions. In this chapter, we will discuss the echocardiographic features of a wide variety of simple and challenging cases of mitral stenosis and mitral regurgitation in the real world.