Abstract: The present invention relates to an improved material and manufacturing method for the extrusion of particle board. It is shown herein that the use of fine particles of lignocellulosic material, typically wood, in combination with an extrudable plastic, allows an increased proportion of wood to be used (typically greater than 50% by weight, wood to plastic) and still obtain an extrudable particle board with good quality surface finish. The use of wood particles finer than approximately 40 mesh is used in the production of extruded particle board in the present invention. A coupling agent is also used consisting of a polyurethane-type coupling agent, added in an amount of approximately 3% by weight, to the extrusion mixture prior to extrusion. This combination of fine wood particles and the above coupling agent yields good quality extruded particle board having a majority of the composition thereof consisting of wood or other lignocellulosic material.