Prediction of ultrafiltration performance during clarification of pre-treated stevia extract by cross flow ultrafiltration in a rectangular cell is presented in this work. The steady state performance is modeled by using classical film theory. The transient state behaviour is quantified by using a model available in literature. In the model, higher molecular weight solutes are clubbed in one gel-forming component and Stevioside is assumed to be other component. In the process of modeling, the gel characteristics are estimated. Both total recycle and batch concentration mode of operations are modeled. The model results are in good agreement with the experimental data. (C) 2012 Elsevier Ltd. All rights reserved.