CuO spheres composed of finely arranged nanobricks were synthesized by simple and facile hydrothermal process and used as efficient electron mediators for the fabrication of highly sensitive non-enzymatic glucose sensor. The CuO spheres were synthesized at low-temperature of -30 degrees C and characterized in terms of their morphological, compositional, and structural properties. The morphological investigations revealed that the synthesized CuO powder possess spherical shapes and made of several CuO nanobricks. The detailed structural characterizations exhibited that the synthesized CuO spheres are nanocrystalline and possessing monoclinic structure. The fabricated glucose sensor based on CuO spheres exhibits a high sensitivity of -164.2523 microA mM(-1) cm(-2) and experimental detection limit of -39 microM with a quick response time of -10.0 s. The presented work shows that the easily prepared CuO nanomaterials can be used as efficient electron mediators for the fabrication of high sensitive non-enzymatic glucose sensors.