Seismic performance of slopes can be assessed through the pseudo-static approach, where the inertial effects are represented by equivalent static forces proportional to the self-weight of the unstable mass via the seismic coefficient k. In this study, the seismic coefficient is calibrated against given threshold values of permanent displacement accumulated during the seismic event. The permanent displacements are evaluated through the rigid-block Newmark model from an up-to-date version of the Italian seismic to obtain novel median and upper-bound empirical relationships expressing the seismic-induced permanent displacements d as a function of slope resistance, given in terms of the critical seismic coefficient, ky, and of the Peak Ground Acceleration, PGA. Compared to existing models, the proposed semi-empirical relationships are more suitable for the application to the Italian seismicity and are used for estimating the seismic coefficient k to be adopted in the seismic analyses of slopes, in the framework of the Performance-Based Design (PBD).