The Pseudo-Spectral Time Domain (PSTD) method is an alternative time-marching method to classical leapfrog finite difference schemes in/nthe simulation of wave-like propagating phenomena. It is based on the fundamentals of the Fourier transform to compute the spatial derivatives/nof hyperbolic differential equations. Therefore, it results in an isotropic operator that can be implemented in an efficient way for room acoustics/nsimulations. However, one of the first issues to be solved consists on modeling wall absorption. Unfortunately, there are no references in the/ntechnical literature concerning to that problem. In this paper, assuming real and constant locally reacting impedances, several proposals to/novercome this problem are presented, validated and compared to analytical solutions in different scenarios.