In this work, cupric and cuprous oxide nanowires were successfully synthesized through thermal oxidation of copper substrates in a three zone horizontal tube furnace over temperatures ranging from 300 to 800℃. Processing parameters, including temperature, pressure, heating time, type of gas and flow rate, were varied and investigated in terms of their influence on the morphology, aspect ratio, composition and density of the nanowires. Scanning electron microscopy studies show that these nanowires controllably ranged in diameter from 40 to 400 nm with lengths of up to 60 µm and the varying density was a function of the growth temperature and reaction time. High resolution transmission electron microscopy and x-ray diffraction studies were conducted to further identify the chemical composition, crystal structure and growth direction of the nanowires. Additionally, the growth mechanism has been proposed. This study with physical property measurements demonstrates that copper oxide nanowires are attractive choices for future applications in lithium-copper oxide batteries and optoelectronics at nanoscale.