Rice is the primary food for over 40% of the world's population, with about 596 million tons of rice and 570 million tons of rice straw produced annually worldwide. At present, most of these residues are burnt in situ after harvest. The field burning of rice straw and other agriculture residues results in serious environmental issues and wastes precious resources. Faced with worldwide shortages of forest resources, environmental pollution and waste of biological resources resulting from field burning of rice straw and other agriculture residues, there has been a revival of interest in using rice straw and other agriculture residues to produce building materials including composite panels. This research aims to evaluate mechanical and physical properties of particleboard made from six different categories of hammer-milled rice straw and two types of resin. The performance of straw particleboard is highly dependent upon the straw particle size. The static bending and internal bonding strength of polymeric diphenylmethane diisocyanate (pMDI) resin based boards initially increase then decrease with decreased particle size. Thickness swelling, water absorption, and linear expansion of particleboards decrease with increased particle size. Compared with pMDI resin bonded panels, rice straw particleboard bonded using urea-formaldehyde resin exhibits much poorer performance. Optimized panel properties exceeded the M-2 specification of American National Standard for Wood Particleboard. This research was conducted as collaboration between scientists at FPL in the Engineered Composites Science research work unit and Egyptian National Research Center.