The study of the mechanism of superconductivity in high-T-c copper oxide superconductors requires knowledge of their simplest mother material, CuO. We present a novel method for single-crystal growth of CuO to ensure high crystal quality for physics study. Large CuO crystals with dimensions up to 14 x 3 x 0.3 mm(3) were grown in a closed 20 phi mm quartz glass tube by chemical vapor transport using CuI and BaO2. The evaporating property of CuI and the oxygen-releasing nature of BaO2 at high temperatures were used to obtain a growth-zone on-site oxidization of the evaporated copper to produce rapid crystal growth of CuO. We obtained impurity-free single crystals of CuO with a room-temperature electrical resistivity of about 10(5) ohm cm with an activation energy of 0.11 eV.