The kinetics of the adsorption of the protein BSA on the ion exchanger Q-Sepharose FF were measured for several values of the pH and ionic strength, using several techniques. The measurements were best described with a model incorporating both surface and pore diffusion and with the chemical potential gradient as the driving force for diffusion. The surface-diffusion coefficients from this model show an inverse exponential dependency on the binding strength. This dependency can be explained by an activated jump mechanism. The pore-diffusion coefficient is much lower than that in free solution, which is probably caused by a combination of steric and electric exclusion.