Samples of mordenites with variable Si/Al atomic ratio and different counter-ions were exchanged with copper ions by two methods e the conventional treatment in water solution and by microwave-assisted procedure. The zeolite-solution ratio and the concentration of solution were kept equal for both procedures. We report on the results of XRD, TGA and XPS studies. The XPS analysis confirms that despite observed differences in the spectra of the samples the copper ions are in the þ2 oxidation state. The preparation method influences copper and water content and copper surrounding, but does not change the electronic state of copper ions.