The separation of the proteins bovine serum albumin (BSA) and myoglobin (Mb) was achieved experimentally by ion-exchange simulated moving bed (IE-SMB) using a salt step elution in an SMB bench-scale unit. The BSA adsorption equilibrium at different salt concentrations was determined by frontal analysis. A phenomenological mathematical model, i.e., the general rate model coupled with steric mass action equilibrium, was used and validated against fixed-bed dynamic adsorption experiments at different salt concentrations. The separation region was computed, and the operating conditions for an SMB experiment were selected within the obtained region. The chosen operating point was experimentally tested, and purity, recovery, and productivity of the BSA on the extract were 96%, 99%, and 4.93 × 10 −3 mol protein •kg ads −1 •day −1 and for the Mb on the raffinate were 99%, 96%, and 4.77 × 10 −3 mol protein •kg ads −1 •day −1 , respectively.