Single crystal growth of CuO, synthetic tenorite, was accomplished in oxygen atmosphere by the chemical vapor transport technique. We present the first systematic study of the growth of CuO in various partial pressures of oxygen. Crystals were grown using trace, 0.1, and 0.5 atm partial pressures of oxygen. The growth temperatures used were 820 and 865 °C. Typical dimensions of the crystals obtained were 1 × 2 × 0.25 mm. We have shown that the stoichiometry of single crystal CuO can be controlled during the growth process. The crystals exhibited cation deficient stoichiometry, Cu1−xO, with x increasing from less than 0.005 with no added oxygen, up to 0.05 with 0.5 atm O2 when grown at 865 °C.