This study is a case report, which presents a case of severe mitral regurgitation in a 77-year-old man. Two-dimensional transesophageal echocardiography (TEE), regurgitant jets directed anteriorly in early systole and centrally to laterally in late systole were seen, while three-dimensional TEE showed a flail posterior middle scallop not only angulated centrally, but also laterally, which provided insight into the mechanism of mitral regurgitant jet direction. This case demonstrates the clinical usefulness of 3-dimensional TEE for identifying the mechanism of mitral regurgitant jets. The institution where the figures and the videos were recorded: Division of Cardiology, Mazankowski Alberta Heart Institute, University of Alberta Hospital, Edmonton, Alberta, Canada.