Bimetallic Pt-Cu/gammaAl(2)O(3) catalyst has been prepared by controlled deposition of copper onto platinum particles according to a redox reaction between hydrogen, pre-adsorbed on metallic platinum, and Cu2+ ions in water. This catalyst has been submitted to either oxidizing or reducing treatments, at ambient temperature or at 400degreesC. The interaction between copper and platinum in the bimetallic catalysts was estimated from temperature-programmed reduction (TPR) profiles, determined after various pre-treatments, and compared to that of a fresh catalyst. It was demonstrated that reducing and oxidizing pre-treatments noticeably affect the interactions between platinum and copper and consequently the catalytic activity for nitrate reduction in water.