Poly(ethylene oxide) (PEO), poly(acrylic acid) (PA), dextran, and some oligomeric saccharides were found to be adsorbed from the aqueous phase on a dealuminated FAU-type zeolite (Si/Al = 110). PEO was also adsorbed on a MFI-type zeolite (Si/Al > 1000), but dextran was not. Inulin and levan were excluded from the FAU-type zeolite. Addition of ethanol (dextran) or increase of pH (PA) caused a strong decrease of the adsorption equilibrium. The Fickian diffusity D of the trimer of dextran (isomaltotriose, M(W) = 504) related to that in the aqueous bulk phase D-0 was D/D-0 = 10(-3) and decreased to D/D-0 = 10(-8) at M(W)= 40 000. D/D-0 values for PEO (M(W) = 9000, 20 000, and 40 000) in the FAU zeolite were situated between 2 and 5 x 10(-7). The high specific interaction indicates that the polymer not only is deposited on the surface of the zeolite crystal but must penetrate to some extent into the pores. The FAU zeolite can selectively adsorb oligomers and polymers containing alpha(1-6) glycosidic linkages (raffinose, stachyose, isomaltotriose, dextran) while those built up by beta(1-6) or alpha,beta(1-4) bonds are sterically excluded.