The relationship between Brinell hardness and tensile strength of wood plastic composites (WPC) as a function of wood filler content was investigated. The sawdust flour was compounded with polypropylene at 30%, 40% or 50% (by weight) content with and without coupling agent, maleic grafted polypropylene with anhydride, in a twin screw co-rotating extruder. Test specimens were produced by injection moulding process from the pellets dried to moisture content of 1%. The relationship between Brinell hardness and tensile strength for all the filler loading levels was studied using linear regression method. The strong correlation was found between the Brinell hardness and tensile hardness of the WPCs as the filler content was between 30 and 40 wt%. The strong correlation showed that the Brinell hardness could be a good indicator for tensile strength of the WPCs. (C) 2013 Elsevier Ltd. All rights reserved.