Wood pieces of a heavy hardwood Neobalanocarpus heimii (King) P. S. Ashton and a light hardwood Shorea macroptera Dyer were used in decomposition experiments with termite-exclusion and control trays on the forest floor of the Pasoh Forest Reserve, West Malaysia to determine effects of wood quality on termite-mediated wood decay. Shorea macroptera had a significant loss of C in the presence of termites while Neobalanocarpus heimii showed no significant termite effect. Neobalanocarpus heimii and S. macroptera both accumulated N in the absence of termites, but S. macroptera lost it when termites were present. The C/N ratio decreased with and without termites as decay proceeded in both species. Neobalanocarpus heimii accumulated P, but S. macroptera lost it with and without termites. The C/P ratio decreased in N. heimii, but did not change in S. macroptera. Decomposition was considerably enhanced by termites in S. macroptera, but not in N. heimii, indicating that termite foraging activity was affected by the different wood qualities of the two trees. The qualities responsible for the differences and how different wood qualities affect nutrient cycling in the tropical rain forest ecosystem are discussed.