Generalized criteria for the determination of fouling mechanism during cross flow membrane filtration are obtained. Two mechanisms, namely, complete pore blocking and cake formation over the membrane surface, in sequence, are considered. A set of three non-dimensional parameters have been evolved to control the mechanism of flux decline during filtration. Depending upon the relationship of these parameters, the various characteristic filtration regions have been identified. The effects of various parameters on the relative importance of both the resistances (complete pore blocking resistance and cake resistance) are analyzed. For example, steady state value of the permeate flux has profound influence on the onset of cake formation as well as the dynamics of the complete pore blocking phenomena. One can achieve higher permeate flux for a suitable combination of parameters in all the three regions. (C) 2009 Elsevier B.V. All rights reserved.