The purpose of this paper is to present the predicted extraction of nimbin from neem seeds using supercritical CO2 when only the molecule structure of nimbin is known. Group contribution methods (GCM) were used to estimate pure component properties. equations of state (EoS) to estimate the pressure/volume/temperature (PVT) behaviour and fugacity coefficient of solute in the solute-solvent mixture. Transport properties were estimated using available correlations and a shrinking core model was used to predict the extraction yield. The model predictions were compared with experimental data; the effect of CO2 flow rate (0.24-1.24 mL/min), temperature (308-333 K), pressure (10-26 MPa), particle size (0.575-1.850 mm) and weight of neem kernel powder (1.0-2.5 g) were investigated. The predicted results were found to agree well with the measured results and the model was able to explain the presence of optimum yields that were observed experimentally. (C) 2009 Elsevier B.V. All rights reserved.