The electrical properties and microstructural characteristics of solid-state synthesized CuGaO 2 ceramics were investigated. Undoped CuGaO 2 ceramics exhibited p-type conductivity with a Seebeck coefficient of 780μV/K and a room temperature conductivity of 0.0033S/cm. Examination of the microstructure of CuGaO 2 ceramics revealed the existence of thin laminar twins oriented along the {0001} basal plane with thickness varying from several to several tens of nanometers. Doping with Ni 2+ and Mg 2+ did not result in a significant increase in conductivity and doping with Sn 4+ resulted in a remarkable decrease in conductivity. With evidence from diffraction data on Sn-doped ceramics, it is proposed that the Sn 4+ was ionically compensated with Cu vacancies.