Background and objectives: Impregnation of wood with different monomers and their conversion to the un-leachable reacted polymers inside the wood causes a new product which is called wood polymer. The furan compounds such as Furfuryl alcohol (FA) is commercially used for wood modification, producing then wood polymer. Wood is impregnated with FA, convert to the polyFA by heating. Furfural which is in fact the primary raw material in the manufacture of FA is extensively manufactured in Iran from residues of sugar cane. Furfural could not be easily polymerized alone like FA; but it is an aldehyde which can react with urea to make polymer network. In this study, the possibility of furfural/urea polymer along with acidic catalyzer (maleic anhydride) was evaluated for the improvement of physico-mechanical properties of birch wood. Materials and methods: Birch wood (Betula sp.) imported from Russia was used for experiments. With a double treatment procedure Furfural+Urea/Maleic anhydride was impregnated into the wood according to a 2 steps vacuum/pressure technology: (1) diluted furfural in water and methanol, followed by (2) Urea/Maleic anhydride aqueous solution. For making comparison between the results, a commercial formulation based on the FA was also used as a reference. The mixes impregnated into the wood were polymerized by heating. Then, different physico-mechanical properties of wood samples were measured according to the standard guidelines of ISO 13061 series. Results: The proportion of Furfural+Urea/Maleic anhydride was appropriately selected, and approximately 60 to 80% were converted to the polymer. The leaching rate of the products once polymerized within the treated wood was around 4% which is comparable to the results of commercial formulation based on FA. The weight percentage gain (WPG) of the wood samples varied between 27 to 57% depending on the furfural concentration in the treatment solutions. Despite the bulking effect, the density of samples afte