This paper reports synthesis, crystal structure and electrical properties of Cu-doped CdO (CdO:Cu) powders. X-ray diffraction shows that majority of the samples are monophase and has the cubic structure. The limit solubility of Cu ions in CdO lattice is found to be 2mol% (after heating at 900°C), whereby the impurity phase was determined to be the monoclinic-CuO. For monophase CdO:Cu samples synthesized at 900°C, the lattice parameter decreased with increasing Cu concentration. Electrical conductivity of undoped CdO and 2mol% Cu-doped CdO (after heating at 900°C) were found to be 79 and 191Ω −1 cm −1 , respectively, at 100°C and 912 and 1549Ω −1 cm −1 , respectively, at 900°C. Thus, it appears that electrical conductivity slightly increases with Cu doping. Finally, the activation energy of monophase CdO:Cu (after heating at 900°C) is shown to decrease with Cu concentration.