The volumetric overall mass transfer coefficients of an Oldshue-Rushton column have been measured using an axial diffusion model, applying two different liquid-liquid systems. The effects of the operating parameters such as rotor speed and dispersed and continuous phase velocities on the volumetric overall mass transfer coefficients have been investigated. The rotor speed was found to have a more profound effect on the column performance. The phase flow rates had little influence on the mass transfer performance. The previous models for estimation of the overall mass transfer coefficient were reviewed and their predictions were compared with the experimental data. All of the previous models failed to properly predict the experimental results under the operating conditions. Therefore, an empirical correlation was proposed for enhancement factor as a function of Re number, Eo number and dispersed phase holdup. This correlation relatively accurately predicted the mass transfer coefficients, so it could be applied to design the Oldshue-Rushton columns. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.