In order to evaluate the feasibility and accuracy of intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) in patients referred for mitral valve prolapse (MVP) repair, two-dimensional (2D) and 3D TEE were performed in the operating room in 46 patients. 2D and 3D TEE correctly predicted MVP localization in 38 (90%) and 36 (86%) patients, respectively (p = NS). The width of the prolapse and the posterior circumference of mitral annulus were measured using 3D TEE, and found to correlate with surgical findings. These 3D data, which cannot be obtained by 2D echocardiography, may be of value to the surgeon when performing mitral valve repair.