The mass transfer of bovine serum albumin onto a stack of cibacron blue cellulose membranes in the loading and elution stages were studied. The breakthrough curves obtained in the loading stage were fitted to the pore and the lumped kinetic (LK) models, respectively. Then experimental data obtained in the elution stage were described by using the LK model in which the kinetic equation, the initial and the boundary conditions were rewritten according to the operation. For the breakthrough curves it was found that the contribution of the sorption kinetics to band broadening was significant whereas that of axial dispersion was negligible. In contrast, both of these contributions were significant to the profile of the elution curve. By studying the mass transfer kinetics in the elution stage, information about the influence of the module geometry on the performance of affinity membrane separations may be obtained.