In this paper, we embed the minimization scheme of an automatic 3D non-rigid registration method in a multi-scale framework. The initial model formulation was expressed as a robust multiresolution and multigrid minimization scheme. At the finest level of the multiresolution pyramid, we introduce a focusing strategy from coarse-to-fine scales which leads to an improvement of the accuracy in the registration process. A focusing strategy has been tested for a linear and a non-linear scale-space. Results on 3D Ultrasound images are discussed.