It is produced on a large scale by pyrometallurgy, as one stage in extracting copper from its ores. The ores are treated with an aqueous mixture of ammonium carbonate, ammonia, and oxygen to give copper(I) and copper(II) ammine complexes, which are extracted from the solids.  These complexes are decomposed with steam to give CuO.
It can be formed by heating copper in air at around 300–800 °C:
: 2 Cu + O → 2 CuO
For laboratory uses, pure copper(II) oxide is better prepared by heating copper(II) nitrate, copper(II) hydroxide, or basic copper(II) carbonate:  
: 2 Cu(NO) → 2 CuO  + 4 NO  + O  (180°C)
: Cu(OH)CO → 2 CuO + CO + HO
: Cu(OH) → CuO + HO