In the last three decades the forestry sector has been given an important contribution to the economy of Indonesia, and during the period year 1993-2005, it contributed from 1.7 to 3.1 percent. To maintain this contribution, it is needed to have a continuation raw material input, Roundwood. Some studies showed that the supply of raw material for wood-based primary industries such as plywood, sawn timber, and pulp in Indonesia are still continuing. Therefore it needs to know the characteristic supply and demand of the wood-based industry by predicting the elasticity. This paper will discuss elasticity supply and demand of the input market of Roundwood from natural and plantation forests and output market of plywood, sawn timber and pulp. Data used for this study is time series, from the year 1995 until the year 2009. The estimation of the econometric model used in this study was simultaneous (2SLS) equation or ordinary least squares (OLS) if the 2SLS model is not working. Data processed by the Rats processing program. All predicted parameter then evaluated and checked in accordance with the economic theory. However, not all predicted elasticity resulted from this study were used. For those could not use that data taken from references. Demand elasticity of Roundwood from natural forests and plantation forests are mostly priced inelastic.