Mathematical models describing kinetics of adsorption and competitive adsorption of polymers into porous media have been developed. The models predict the constant of adsorption equilibrium, the rate constants of adsorption, of desorption, and of substitution of small polymer chains by large ones, and the maximum amount of polymer that can be adsorbed on a unit area of the surface. Using experimental adsorption data of monodisperse polystyrenes and porous silica, we show that there is good agreement between the kinetic models and the experimental data.