The aim of this study is to determine the feldspar adsorption kinetics and isotherm of Cd(II) and to model the adsorption data with the aid of a metal-surface binary complexation approach. The adsorption of Cd(II) ion onto feldspar was approximated using a triple-site model by the aid of the FITEQL 3.2 computer program calculating the relative distribution of surface species. Experiments were carried out at I=0.1 ionic strength using an inert electrolyte (NaClO4). Of the three metal-binding surface sites of feldspar, it was assumed that (K,Na,Ca,Mg)X represents ion exchangable negative-charged sites, -S1OH silanol groups, and -S2OH pH-dependent aluminol groups. Metal hydrolysis was neglected under the experimental conditions employed, and Cd(II) was assumed to bind to the clay surface as the sole Cd2+ cation. The equilibrium constants of the reactions between Cd(II) ion and the surface sites were calculated using FITEQL 3.2. Cd(II) adsorption on feldspar showed Langmuiran character and pseudo-first order kinetics. The maximum adsorption capacity of feldspar for Cd(II) ions was found as 1.29 mg metal ion/g adsorbent. The results of this study are believed to facilitate the solution of environmental problems like metal ion migration and adsorptive treatment by clay minerals.