The operation of a continuous countercurrent adsorption system is modelled and optimized. The objective is to maximize the recovery of the less strongly adsorbed species in the raffinate for a specified purity of the product. The optimization is carried out for a system with linear and non-linear isotherms. The optimization results indicate that the optimum values of parameters are significantly different for linear and non-linear isotherms. An optimal choice of operating variables corresponding to a compromise between recovery and purity is also suggested.