In this study an attempt has been made to obtain a dimensional analysis based empirical model of ultrafiltration process under stirred condition, which for a given membrane will predict the permeate flux and the rejection during the dynamic as well as the steady state phases of operation from the process conditions applied, viz. pressure drop, stirrer speed, bulk concentration of the filtered species etc. A dimensional analysis by Rayleigh’s method was performed and the obtained dimensionless groups were related with the help of experimentally obtained data in this study, by non-linear regression employing Levenberg and Marquardt technique. Two equations have been obtained, one for the prediction of flux and other for the rejection. The computed results are found to be in good agreement with the experimental data obtained in this study during the ultrafiltration of PEG-6000 by cellulose acetate membrane and the absolute average deviation was found to be within less than 7%.