The effects of different types of salts and salt concentrations on the selectivity in the adsorption of serum proteins have been compared for the amphiphilic agarose-based adsorbents Phenyl-Sepharose, Octyl-Sepharose, butyl-agarose and mercaptopyridine-derivatized agarose. By use of multivariate analysis, the complex interrelationships for the different combined effects were evaluated. From these analyses conclusions about similarities and/or dissimilarities in the mechanisms involved in adsorption of proteins on respective adsorbent were made.