The power draw of a high-shear rotor-stator homogenizer has been characterized in laminar, transitional, and turbulent operation. The power draw is comprised of two components - that associated with mixing and that associated with a bushing and bearings in the device. In turbulent operation, the mixing power draw is influenced primarily by pumping mode (up- or down-pumping), and to a lesser extent, by vessel baffling and other geometric parameters. Mixing power draw can be characterized in terms of power number across the Reynolds number spectrum if an empirical Froude number correction is applied.