Two types of the montmorillonite — humic complex (MMT.HA) were prepared and their sorption properties were studied. X-ray analysis showed changes in the first basal spacing of c-humates prepared by co-coagulation in the comparison with m-humates obtained by mixing and subsequent hydration. Repetitive cyclic voltammetry on the carbon paste electrode modified with MMT.HA proved the influences of sorbed humic acid on Cu(II) sorption onto the MMT.HA.