Single-phase spinel manganese cobalt oxides Mn3−xCoxO4 dense ceramics were prepared for the first time and their structural/electrical property relationships characterized. The electrical properties, that is, the resistivity at 25°C, the energetic constant, and the resistance drift at 125°C, were determined and correlated with the cation distribution. Finally, the electrical characteristics of the Mn3−xCoxO4 system were compare'd with other important classes of manganese-based spinel oxides, Mn3−xNixO4 and Mn3−xCuxO4, already commercialized as negative temperature coefficient (NTC) thermistors. The high values of energetic constant and low resistivities observed in Mn3−xCoxO4 ceramics present a promising interest for such industrial applications.