The poor oxidation resistance of Cu-base alloys limits their applications at high temperatures, and it cannot be improved by conventional Cr alloying because that requires an extremely high Cr content. In this work a chromia scale has been formed on novel Cu-base nanocomposites which contain much less chromium. Cu-Ni-Cr nanocomposites, with the weight percentage ratio of Cu/Ni %1 and various amounts of Cr, were produced by co-electrodeposition of Cu-Ni alloy with Cr nanoparticles which subsequently acted as ''seeds'' for chromia formation. The results of oxidation tests in air at 800°C showed that only 15 wt.% Cr in the nanocomposite was required to form an external chromia scale. Furthermore, the scale consisted only of chromia rather than the duplex scales which form on the conventional alloy even when it contains significantly more chromium.