Recent laboratory studies demonstrate that mixing at the boundaries of stratified and rotating fluids can be described by a relatively simple parameterization. These results are applied to the deep ocean, and by using available field observations, it is argued that mixing at the boundaries can lead to an apparent diapycnal diffusivity in the interior of the deep ocean whose magnitude has an upper bound of 3¿10-5 m2s-1. ¿ American Geophysical Union 1987