Six low-density tropical woods were impregnated with various vinyl monomers and polymerized by irradiation with a60Co source. The wood-plastic combinations were subjected to standard tests of mechanical properties, and their fracture surfaces were studied by scanning electron microscopy. It was found that, even though most mechanical properties are enchanced by addition of plastics, the properties of wood-plastic combinations fall below those of high-density natural woods on a per unit weight basis. The direct observation of fracture surfaces gave indications of non-uniform penetration of the plastic and little bonding between the polymer and cellulose fibres. Although the wood-plastic combinations produced by the present methods may not be recommendable for applications where increased strength is desired on the basis of cost/ quality considerations, they may be suitable for uses where increased abrasion resistance, dimensional stability and lower anisotropy of compressional properties are primary considerations.