Tbe phenomenon of phase inversion in liquid-liquid dispersions produced by shear is examined with respect to the PhYsical properties of the liquids and the operating conditions of the shearing system. The phase inversion point is shown to depend on the wettability of the shearing surfaces by the liquid phases and the viscosity difference between the liquids. High-viscosity liquids were found to prefer to form the continuous phase, particularly when they also wet the shearing surfaces. When the viscosities of the liquids were similar, inversion occurred at roughly equal volume of the phases, with small differences caused by the surface wetting.