The power consumed in mechanically agitated vessels is an important parameter, especially for the energy requirements and the heat and mass transfer efficiencies of these systems. Power consumption does not only depend on the impeller type, the fluid properties and the stirring speed, but also on the geometry of the agitated system, including the impeller spacing and the length of the baffles in the mixing vessel. Information is presented on the combined effects of baffle length and impeller spacing on the total power consumption in vessels agitated by dual pitched blade impellers.