In industrial applications, microstructure inhomogeneities can derive from the manufacturing process and the final mechanical properties of the material depend on the resulting, complex, structural pattern of the constituents. In this paper, Cell Method plane models in the elastic and plastic fields are presented and applied to predict the behaviour of four sintered alloys, where the spatial arrangement of voids within the base material contributes to determine the mechanical behaviour. Unlike the Finite Elements and other methods, the Cell Method is a numerical method based on a direct discrete formulation of equilibrium equations, so that no differential formulation is needed in order to write the balance equations. One of the consequences of the Cell Method direct discrete approach is that no restriction is imposed by differentiability conditions so that the characteristic length of the elementary cell in the discretization can be of the same order of magnitude of the heterogeneities of the structure. Therefore, the Cell Method appears to be particularly suitable to assess the mechanical behaviour of heterogeneous materials. The results of the computations show a very good agreement with the experimental data of the sintered alloys examined.