Pressure filtration of super-compactible cakes is characterized by negligible increases in both the liquid flow rate and the average percentage of cake solids when the applied pressure drop is above a critical value, which is defined as the critical pressure drop Deltap(cR) (Tiller, F.M.; Li, W.P. Strange behaviour of super-compactible filter cakes. Chem. Process. 2000, 63 (9),49) (Tiller, F.M.; Li, W.P. Determination of the critical pressure drop for filtration of super-compactible cakes. Water Sci. Technol. 2001, 44 (10), 171). When operation pressure is beyond Deltap(cR), there will be little effect of pressure on either flow rate or the average % cake solids. Lack of understanding of the strange behavior will lead to problems in design and operation of solid/liquid separation systems. In this paper, theory and numerical calculation of radial flow pressure filtration of super-compactible cakes will be presented. Flow rate and average % cake solids as functions of pressure at different cake thickness are calculated for radial flow filtration of flocculated latex. The critical pressure drop Deltap(cR) is determined as a function of cake thickness.