The presence of a strong electrolyte in mobile phases essentially influences the pH gradient profile generated by chromatofocusing. The variation in the strong electrolyte concentration in the chromatofocusing system is studied. The ionic strength gradient ends far more early than the pH gradient; anomalous segments of the pH gradient profile match the general trend of the ionic strength in the system. The pH gradients obtained under identical conditions on carboxylic sorbents MacroPrep 50 CM and MN are compared. The influence of the KNO3 concentration in the mobile phases on the gradient profiles is studied. Optimum systems are chosen for generating the smoothestlinear pH gradients.