CuO nanostructures were reported for a myriad of applications in diverse areas such as high Tc superconductors, field emitters, catalysts, gas sensors, magnetic storage, biosensors, superhydrophobic surfaces, energy materials etc. In all these applications, structural stability of the nanostructures is very important for efficient functioning of devices with a longer lifetime. Hence, it is necessary to understand the adhesion energy of these nanostructures with their substrates. In this research work, a variety of CuO nanostructures were synthesized directly on Cu foil substrate by varying only the concentration of the reagents. CuO nanostructures, thus grown, were subjected to a nano-scratch test to quantify their adhesion strength with Cu substrate. The adhesion energy was observed to be highest for nanorods and lowest for nanoribbons among all the CuO nanostructures synthesized in this work. Results of this research will be useful in predicting the service life and in improving the efficiency of CuO nanostructure-based devices.