The goal of this work is to determine the role of the particulate alignment on the overall deformation behavior of metal matrix composites, Stress-strain behavior of hard particle-ductile matrix materials were analyzed using finite elements method. The effects of volume fraction and distribution geometry of particles were investigated. The composite microstructure was assumed to be a 3-D infinite periodic array of spherical particles embedded in the matrix. Transversely aligned and staggered unit cell approximations were used for analyzing the particle distribution geometry effects. The effect of particle alignment on the overall stress-strain behavior of the composites was followed through unit cells having different aspect ratios. The strengthening and strain hardening in the hard particle-ductile matrix composite system were found to be controlled primarily by the volume percent reinforcement. Distribution geometry of reinforcement as represented by that the ratio of particle diameter to distance between nearest neighbor particles also has great effect on deformation behavior. (C) 1999 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.