In this research the Discrete Element Method is employed to determine the seismic three dimensional bearing capacity of rectangular foundations. A rigid but moving slip body resting on its base is assumed to define the failure mechanism under the footing. A soil mass enclosed in a three dimensional space with assumed failure surfaces is considered as several discrete blocks connected with Winkler springs. The geometry of the failure surface under the foundation is not fixed and can be altered due to all of the factors affecting the problem. This geometry is determined by six independent angles. The seismic loading can be applied to the soil mass, soil surcharge and foundation loading in a pseudo-static manner. This paper includes the derivation of 3D DEM formulation in a three dimensional state, and several examples solved by means of a developed DEM program to explain the capability of the method and to compare the results with the other methods.