Few papers have reported the power consumption and mass transfer volumetric coefficient measured in mixing vessels equipped with wide-paddle impellers under aeration. In this paper, the power consumption and mass transfer volumetric coefficient were measured in mixing vessels equipped with various wide-paddle impellers under aeration. It was found that the large paddle impeller did not decrease the aerated power consumption, because no large cavity was generated. The mass transfer volumetric coefficients were correlated with the equation of Sato et al. (1989) in an air water system, and those in an air CMC solution system were correlated with the equation of Hiraoka et al. (2003) under turbulent conditions.