The adsorption of guar gum on illite and dolomite was studied as a function of polymer concentration and ionic strength. The adsorption results were correlated with colloid stability of aqueous suspensions of these two minerals. The adsorption density of guar gum on illite was not affected by the ionic strength of the system. Guar gum adsorption on dolomite was found to strongly decrease at higher electrolyte concentrations. Low concentrations of guar gum brought about flocculation of the minerals while higher dosages led to steric re-dispersion. Results presented here are compared with previously published results for carboxymethyl cellulose (Pawlik et al., J. Colloid Interface Sci. 260, 251-258 (2003)).