The effects of ethanol-water and methanol-water mixtures on Zn and Cd sorption onto Wyoming bentonite and illite were investigated at low initial metal concentration (≤10-5 M) and low ionic strength (2.5 mM Ca(NO₃)₂). In these alcohol-water mixtures, no significant effect of pairing on the partitioning coefficients of Cd²⁺ and Zn²⁺ to clay minerals was recorded. For all cosolvent fractions, the percent coverage of Zn and Cd to clay minerals was low (≤ 5%) and independent of the solution dielectric constant except for Zn at 10 μM initial metal concentration. Cadmium sorption to both bentonite and illite in various cosolvents and at various cosolvent fractions was independent of the solvent dielectric constant. Zinc sorption varied significantly between clay types, cosolvent type and cosolvent fraction. The partitioning of Zn to bentonite increased from 0 to 10% alcohol-water fraction and decreased after 10%. The same pattern was observed for the partitioning of Zn on illite in methanol-water mixtures. In ethanol-water mixtures, K_f for Zn on illite increased continuously from 0 to 50% ethanol. In this experiment, the equilibrium solution pH was measured and ranged from 4.5-7.0. In this range and for bentonite clays, pH is believed to have minimal effect on Cd²⁺ and Zn²⁺ sorption. Based on this work, no general mechanism of metal retention in cosolvents can yet be described partly because metal- partitioning appears to be species, surface and solvent specific, at least for the two metals studied