As an alternative to the Rushton turbine impeller (RT), the Elephant ear impeller (EE) has been indicated as suitable for the cultivation of shear-sensitive cells such as animal cells and filamentous fungi. In the present work the average shear rate (γ̇av) was evaluated and compared in a conventional bench-scale stirred-tank bioreactor, using different impeller configurations such as the Rushton turbine and the Elephant ear turbine in the down-pumping (EEDP and up-pumping (EEUP) modes. Based on recent methodology, correlations to estimate the average shear rate (γ̇av) were obtained for the different impellers according to the rotational impeller speed (N), specific air flow rate (φair), and rheological properties of non-Newtonian pseudoplastic fluids. Values of γ̇av predicted by the proposed method were within the range of values calculated by the correlations found in the literature, indicating that the proposed method generates reliable values of γ̇av. The γ̇av values obtained for the RT and EEDP impellers increase with the increase of N and decrease with the increase of φair for all non-Newtonian fluids. In contrast, for the EEUP impeller γ̇av values decrease with the increase of N and φair. The negative influence of φair in γ̇av at constant agitation (N) for all impellers was attributed to the increase of the gas hold-up by the increase of φair. EE impellers generated values of γ̇av lower than that observed in the system equipped with the RT impeller. EEUP was the impeller that combined good oxygen mass transfer and low shear, appropriate characteristics for its use in bioprocesses involving shear-sensitive microorganisms. The importance of the correlations developed in the present work is that they allow estimation and comparison of the shear conditions in cultures as a function of the operating conditions (N, φair), rheological properties of the fluid (K and n), and volumetric oxygen transfer coefficient (kLa) in conventional bioreactors equipped with different impeller configurations in turbulent flow regime. © 2012 Elsevier Ltd.