The rigid polyurethane (PU) with apparent density about 40 kg/m3 was prepared using commercial polyols and polyisocyanate. This reference petrochemical formulation was modified with natural and renewable components such as date palm particles (DPP). The goal of this investigation was to reduce the environmental impacts, and reduce the cost of the petroleum based polyurethane (PU) by obtaining polyurethane/date palm particles (PU-DPP) composites with the heat insulating and mechanical properties similar or better as in the case of the reference material (PU). The composites were prepared with different (DPP) loading; 5%, 10%, and 20% (by weight). The results showed that heat insulating and mechanical properties of the (PU-DPP) composites were comparable with those from reference petrochemical formulation (PU). On the other hand these mechanical and thermal performances are competitive with those of other insulating material available on the market. Hence the (PU-DPP) is a good candidate for development of efficient, low cost, and safe insulating materials.