Copper adsorption capacity of the illuviation (E) and accumulation (B) horizons of a Luvisol profile was studied in high ionic strength NaCl solution and at pH 4-5. The maximum copper adsorption calculated by Langmuir equation was 0.052 mol/kg Cu (3 304 mg/kg Cu) for the E horizon, and 0.071 mol/kg (4 512 mg/kg) Cu for the B horizon. The differences arise from the different mineral composition of the distinct horizons. Hydrous iron oxides and swelling chlorite/vermiculite in the accumulation layer increase Cu adsorption capacity, while hydroxy-interlayering in vermiculite, and absence of iron oxides decrease Cu uptake of the eluviated horizon. Based on XRD studies, measurable fraction of Cu was sorbed in the interlayer space of vermiculite by ion exchange mechanism. This adsorbed Cu caused the loss of expansion capacity of the vermiculite