A modification of the shear induced diffusion model for membrane dominated microfiltration experiments of polydisperse suspension is presented. The particle adhesion concept provided estimation of the average particle radius in the various regions of the membrane filter. This approach enabled the estimation of the solidosity at the cake surface and the cake resistance from a knowledge of the feed particle size distribution, the cake thickness and other operating conditions using the experimental data for polydisperse suspension microfiltration of Romero and Davis (J. Membr. Sci. 62 (1991) 249) where large sizes of particles were used in a rectangular plate microfilter. This analysis showed that the solidosity varies along the membrane surface with maximum predicted solidosities ranging from 0.57 to 0.66. Estimated cake resistance, 2.84 x 10(8)-4.95 x 10(9) m(-1), confirms the hypothesis of negligible cake resistance as compared to typical membrane resistance, 1 x 10(11) m(-1). (C) 2002 Elsevier Science B.V. All rights reserved.