Researchers have identified copper oxide nanoparticles (CuO-NPs) as a key of interest because of their unique shape- and size-dependent bio-medical properties. Researchers have discovered and invented a variety of methods for the synthesis of CuO-NPs under physical, chemical and biological approach. In this review paper, we give an overview of the preparation of CuO-NPs through various methods and also their applications in the bio-medical field. The main aim of this paper is to keep up to date with the myriad ongoing methods of NPs’ synthesis and also examine their applications, especially in the field of medicine.