A model is developed to simulate ion exchange performance within a fixed, annular ion exchange bed. In the bed the injected solution flows radially from the inlet located at the annular bed’s axis to the outlet located at the bed’s periphery. The model considers radial dispersion to be a function of the solution velocity and assumes instantaneous pointwise equilibrium exists throughout the bed between the ions in the solution and the exchanger phases. Experiments to validate the model are conducted using a wedge-shaped radial ion exchange bed having 30 degrees of are and containing commercially-available ion exchange resin. The performance of the radial bed is studied for both the exhaustion and regeneration cycles for the Na+-H+ and Ca2+-H+ cation binary systems. The predictions made by the radial ion exchange performance model are found to be in close agreement with the experimental observations for the systems studied.