The purposes of this study were to derive conversion factors from specific gravity and carbon content of timber in order to gain an accurate estimation of carbon sequestration of forest resources and forest products in Taiwan. In this study, the specific gravity and carbon content of 47 main timber species including 24 woods native to Taiwan and 23 exotic woods were measured. The results indicate that the average carbon contents for native softwoods and hardwoods in Taiwan are 48.2 1% and 46.91%, and for exotic hardwoods is 49.06%. All of these values are lower than the theoretical value for the carbon content of wood ~50%. The conversion factors for carbon sequestration of native timbers lie between 0.15 and 0.36.