Multiplane transesophageal echocardiography is a useful tool to study mitral regurgitation. We evaluated the diagnostic accuracy of multiplane transesophageal echocardiography performed according to the guidelines of the American Society of Echocardiography. We used 4 midesophageal and 2 transgastric views in 313 patients with degenerative lesions, endocarditic lesions, or both to identify regurgitant defects, comparing transesophageal echocardiography results with surgical findings. The overall diagnostic accuracy using individual scallops was 97.2% (P <.00001) with a sensitivity of 96.6% and a specificity of 97.6%. Considering the single sections of the mitral valve, an accuracy of 98%, 97.1%, and 98%, was found, respectively, for the lateral, middle, and medial third of the anterior leaflet. For the posterior leaflet, the accuracy was 98% for the lateral scallop, 98.4% for the middle, and 96.1% for the medial. This strategy provides good accuracy in diagnosing both simple and challenging mitral-valve lesions and its widespread use should be recommended.