An attempt has been made to improve dimensional stability and resistance to biological deterioration of rubber wood (Hevea brasiliensis) against fungal decay via preparation of wood-polymer composites (WPC). Monomer formulations based on methyl methacrylate (MMA), butyl methacrylate (BMA), acrylonitrile (AN) and styrene (ST) were used for impregnation and cobalt-60 gamma radiation source for polymerisation. Dimensional stability was measured in terms of anti-shrink efficiency (ASE), and biological deterioration in terms of weight loss caused by white and brown rot fungi during a period of 12 weeks exposure. Polymer loading (PL), in general, increased with the radiation dose upto 30 kGy. Maximum PL (similar to26%) was observed with BMA and minimum (similar to13%) with AN based formulations. Whereas, ASE improved proportionately with PL. Partial replacement of AN with MMA did not show significant effect on the said properties, that with ST lead to maximum ASE and resistance to fungal decay.