Mitral valve (MV) repair has become the preferred treatment for mitral regurgitation associated with degenerative MV disease. Although the functional benefits of early MV repair are known, the associated alterations in left ventricular (LV) shape have not been studied. The aim of this study was to evaluate serial changes in LV performance and 3-dimensional (3D) shape after MV repair using a new analytic technique. Fifty patients (mean age 59 ± 12 years) with severe asymptomatic mitral regurgitation and ejection fractions >55% who underwent MV repair were enrolled. Transthoracic real-time 3D echocardiography was performed the day before and 6 and 12 months after MV repair. An age-matched control group of 50 normal subjects was studied for comparison. Endocardial surfaces were extracted to compute 3D shape indexes of sphericity and conicity, which were compared in patients between different time points and versus the normal group. Postoperatively, LV volumes were decreased compared to presurgical values. Ejection fractions were slightly decreased 6 months after surgery but had restored by 12 months. These changes were associated with modifications in end-diastolic LV shape: before surgery, compared to normal controls, sphericity was augmented and conicity was decreased; at 6 months, these shape changes were reversed, with no further improvements at 12 months. In conclusion, patients with asymptomatic mitral regurgitation and preserved LV function already exhibit changes in LV shape. Early MV repair leads to near normal morphology after surgery, indicating the benefits of this procedure. Real-time 3D echocardiography and novel 3D shape analysis allow detailed serial examination of the complex relation between LV performance and shape.