The purpose of this investigation was to compare the heartwood and sapwood properties (1) of several woods before and after impregnation with methyl methacrylate monomer and polymerization using the catalyst-heat system. The impregnation and curing procedure was the same as Meyer reported (2). Azobisisobutyronitrile, free radical catalyst, was used instead of the benzoyl peroxide. Vazo is duPont's name for this catalyst (3). Eight species of wood were investigated, seven hardwoods and one softwood.