The influence of the ethanol in ethanol-aqueous mixtures on the formation of Cu(II) -EDTA and Fe(III) -EDTA complexes was investigated. A solid membrane cupric ion-selective electrode as the titration sensor was used for direct determination of copper(II) in the presence of different quantity of iron(III) in non-aqueous media. The direct determination of copper(II) ion is based on the formation of Cu(II) -EDTA complex, which is quantified by measurements with a cupric electrode. The measurements were carried out in 45% v/v ethanol.