Proton/cadmium(II) ion exchange kinetics on sulfonated polystyrene resins of type gel, macroporous, and hypercross-linked were investigated using a potentiometric method in conditions favoring a particle diffusion-controlled mechanism. The data were modeled with different quasi-homogeneous resin phase kinetic models and with the Ruckenstein et al. bidisperse pore model. The interdiffusion and self-diffusion coefficients were obtained and reported. The diffusion coefficients on resins with different texture slightly decrease in the series hypercross-linked >= gel > macroporous resins. The evaluated ratio between the sulfonic groups grafted in micro- and macropores was (1)/(60) for the macroporous resin and (1)/(100) for the hypercross-linked one. The evaluated Cd2+ self-diffusion coefficients were 8.4 x 10(-12), 6.4 x 10(-12), and 9.1 x 10(-12) m(2) s(-1), while the evaluated H+ self-diffusion coefficients were 1.7 x 10(-10), 1.4 x 10(-10), and 4.1 x 10(-10) m(2) s(-1) on gel, macroporous, and hypercross-linked resins, respectively.