The objective of this research was to investigate the influence of particles size on physical and mechanical properties of particleboard made with iroko raw material using organic binder of the African locust husk (Parkia Biglobosa). For this study, four granular (g) classes were used: G1 (raw sawdust, not sieved); G2 (g ≤ 0.8 mm); G3 (0.8 mm < g ≤ 1.6 mm) and G4 (1.6 mm < g ≤ 5 mm) with five different binder rates (5%, 7.5%, 10%; 12.5% and 15%). The panels produced from these different elements were characterized. The mechanical properties (MOE, MOR, E and MOT) determined by the bending and tensile strength tests met the threshold set by ANSI A208.1 (2009). The density values showed that all particleboard were medium density panels except for the ones made with particles size G3 (1.6 mm <g ≤ 5 mm). This study revealed that mechanical and physical properties of such experimental panels were influenced by the particle size. Particles with smaller size provide high density and decrease void inside the panels improving physical properties by reducing swelling rate and water absorption. On the other hand, decreasing particles size decrease the mechanical properties