Magnetic Resonance Imaging (MRI) is recognized as a relevant modality for dynamically imaging the heart anatomy and function, and achieving satisfying qualitative diagnosis. Reliable methods for quantitatively analyzing cardiac MR images remain, however, to be elaborated. This paper presents a novel approach for measuring myocardial and wall motion from MRI sequences. Based on efficient voxel-based statistical non rigid registration, it allows for automatically extracting local/global deformation parameters at the voxel, myocardial segment and whole myocardium scales. Its performances for assessing the myocardial contractile function are illustrated both for the normal heart and for dilated cardiomyopathies (DCM)