Quaternary sediment deformation structures of Madrid Basin have been analyzed. We get a high symmetry degree in deduced stress tensor trends, concluding that there are a regional stress field with NW-SE Shmax trend. Local stress field (NE-SW) is also deduced. This deformational process has been active since Middle-Upper Miocene, and it is still active as can be seen from seismological data. Largest deformation structures occur in the centre of the basin, where gypsum outcrops appear. It seems that halokynetics processes potentiated this tectonic deformation. Analyzed areas and ages of deformed quaternary sediments, leads us to the conclusion that intense faulting occured in Lower-Middle Pleistocene. Related paleoseismic structures appear