Low energy ball milled W/Cu powders were used for metal injection molding (MIM) in order to overcome the low powder volume fraction of MIM parts after debinding as well as the inherently poor sinterability of the W-Cu powder compacts. Ball milling was carried out using commercial fine Wand Cu powders to form a powder mixture suitable for injection molding. W powders showed no change in either size or shape during the milling process, but the ductile Cu powders were easily deformed to a three-dimensional equiaxed shape, having a particle size comparable to that of W powders. This modification of powder characteristics by ball milling resulted in an improvement of the solid loading of roughly $58\%$, maintaining a high and uniform powder packing density in the feedstock. The densification behavior of W-Cu MIM parts is also discussed on the basis of the relationship between Cu composition and W particle size.