A mathematical model for predicting filtrate flux decay in cross flow is given. The formation of a cake in cross-flow filtration results in a decay of the filtrate flux. The growth of the cake is dependent upon the shear at the cake's surface and the filtrate flow normal to it. It is possible to predict the growth of the filter cake thickness in cross-flow based the concept that the cake surface growth is controlled by the adhesion of particles. This yields criteria for growth and also determines the filtrate flux and its decay. Unlike most previous studies, the parameters required for estimating the filtrate flux can be calculated directly based on operating conditions or they can be determined from independent measurements. Example calculation results are given and further improvement of the procedure discussed. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.