Emulsification with high porosity micro-engineered membranes leads to stable emulsions with a low droplet span when, besides a surfactant in the continuous phase, an additional, suitable surfactant is used in the dispersed phase. This surfactant should exhibit relatively fast adsorption dynamics, which is more critical when the surfactant in the continuous phase has slower dynamics. Dispersed-phase fluxes of up to 92.5 x 10(-6) m(3)/m(2)s could be achieved, which is an order of magnitude higher than previously reported for SPG membrane-based cross-flow emulsification. (C) 2009 Elsevier B.V. All rights reserved.