The theory of fouling dynamics in crossflow membrane filtration is compared with ultrafiltration experiments with suspensions of 0.12 mu m silica colloids. It has been experimentally verified that colloidal fouling in crossflow filtration is a dynamics process from non-equilibrium to equilibrium and that the steady state flux is the limiting flux. With the cake concentration c(g) identified from an independent experiment and the specific cake resistance calculated by Carman-Kozeny equation, the time-dependent flux and the time to reach steady state in the experiments of this study are correctly predicted with the theory of fouling dynamics.