In this study, we investigate the effects of high energy milling under Ar atmosphere on the morphology, size and microstructure of Cu-Cr alloy powders prepared by gas atomization. The attrition milling using stainless steel balls is performed up to 60 hrs. The observation by SEM and TEM shows apparent sequential changes of morphology and size of powders similar to those that are typical for mechanically alloyed elemental powders. Prolonged milling in the steady state regime produces a nano-crystalline structure, consisting of extremely small grains of 20 to 50 nm in size and finely dispersed Cr particles. It is also shown that the uptake of Fe from the stainless steel balls and vessel is appreciable. The microhardness of milled powder increases with the milling time, reaches its peak and then slightly decreases.