Mathematical modeling study for extraction of oil from vetiver root using supercritical carbon dioxide was performed in this study. Mass transfer is based on local equilibrium between solvent and solid. The equilibrium constant between solid and solvent was determined by fitting theoretical extraction yield with experimental constant velocity data. The model was solved numerically. Model estimation was validated with constant residence time and small scale experimental data. Effect of supercritical fluid flow rate, extractor diameter per extractor length ratio, particle diameter and bed void fraction on extraction yield was investigated using the model. (C) 2008 Elsevier B.V. All rights reserved.