Finite element modeling and analysis have been used to analyze the behavior of particle reinforced metal matrix composites for a long while. Up until recently, most of this work involved treating particle as a sphere embedded in a metallic matrix. It was soon realized that these models did not account for the microstructural factors that influence the mechanical behavior of the composite material. We provide examples of the use of two-dimensional (2D) and three-dimensional (3D) microstructure-based FEM models that accurately predict the properties of particle reinforced composite materials. We show that 2D models do capture the anisotropy in deformation behavior induced by anisotropy in particle orientation. The experimentally observed dependence of Young's modulus and tensile strength is confirmed by the 2D microstructure-based numerical model. The two-dimensional modeling, however, has its limitations one models only a two-dimensional section of the real, three-dimensional object. For a realistic comparison to actual experimental values is not possible, one must resort to three-dimensional modeling. A serial sectioning process can be used to reproduce and visualize the 3D microstructure of particle reinforced metal matrix composites. The 3D microstructure-based FEM accurately represents the alignment, aspect ratio, and distribution of the particles; and allows visualization and simulation of the material behavior.