Wood saw dust is being considerably used in reinforcing polymer both from a scientific and a commercial point of view over the last decades. In this study, three different types of wood saw dusts were treated with 10% NaOH solution separately. Both chemically treated and untreated wood saw dust particles reinforced polymer matrix composites were prepared and their tensile strengths and water absorption behaviour were studied. In order to know the water absorption behaviour, both chemically treated and untreated wood saw dust reinforced polymer matrix composites were weathered in water at ambient temperature for different time periods. Experimental results showed that the tensile strength of the composites substantially increases due to chemical treatment of the wood particles. After calculation of water uptake, plot of percentage of water absorption versus weathering period was obtained. It has been revealed that chemical treatment of the reinforcing wood particles increases the water absorption of the composites. Results also indicated that water absorption of the composites increases with increasing percentage of wood particles and weathering period. SEM micrograph of the composites exhibited large cavity and air bubble on the tensile fracture surfaces of the composites. The underlying reasons related to the experimentally observed tensile and water absorption behaviour of the developed composites have been discussed in this paper.