Prediction of ultrafiltration performance in a stirred continuous mode during clarification of pre-treated Stevia extract is presented in this work. The steady state performance is modeled by using classical film theory. The transient state behaviour is estimated by using a model available in literature. In the model, higher molecular weight solutes are clubbed together in one gel-forming component and Stevioside is assumed to be other component. In the process of modeling, diffusivity values of gel forming material, and Stevioside, gel concentration, and other gel characteristics are estimated. The model predictions are in good agreement with the experimental data. (C) 2012 Elsevier B. V. All rights reserved.