The equilibria and kinetics of adsorption of lysozyme and bovine serum albumin on the Fractogel-EMD tentacle-type cation exchanger and the Fractogel-TSK conventional cation exchanger have been studied experimentally by batch stirred-tank methods. Adsorption equilibrium data corresponded well to the Langmuir isotherm. For both proteins, the tentacle-type exchanger exhibited a higher binding capacity than the conventional exchanger. This is attributed to the flexibility of the functional groups in the tentacle-type exchanger which enhances optimal electrostatic interactions. The dynamic data were analyzed by a simplified rate model which lumped mass transfer resistances and intrinsic adsorption kinetics into a single rate constant. For both proteins, it was found that the tentacle-type exchanger showed a smaller lumped rate coefficient than the conventional exchanger. The difference in the values of the lumped rate coefficients was shown to be due to the influence of nonlinear equilibrium constants rather than due to any difference in rate of adsorption.