Biologically fabricated nanoparticles have several applications in numerous fields where bio-mediated nanoparticles emerged as having a major role in green synthesis. In this study, cadmium oxide (CdO) nanoparticles were synthesized using Amaranthus Dubius leaf extract as a reducing and stabilizing agent. Generally, cadmium oxide (CdO) nanoparticles have wide applications as pigments in paints, semiconductors, plastics, the production of batteries and other electronic applications, and also exhibit excellent magnetic, optical and structural properties. Furthermore, in the present investigation, the synthesized samples were characterized using methods such as X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), UV-Visible Absorption Spectroscopy (UV) and Transmission Electron Microscopy (TEM). Using X-Ray Diffraction, the crystalline structure of cadmium oxide (CdO) nanoparticles is identified whereas Fourier-Transform Infrared Spectroscopy is used to identify the molecular interactions taking place in the sample. A reduction in cadmium (Cd²⁺) ions and the optical band gap value is recognized using UV-Visible Absorption Spectroscopy, while Transmission Electron Microscopy shows the spherical nature of cadmium oxide (CdO) nanoparticles. Thus, the present study concludes that the biologically synthesized cadmium oxide (CdO) nanoparticles exhibit enhanced morphology and are non-toxic to the environment. This synthesis method ensures the rapid production of metallic nanoparticles which is environmentally friendly, simple and economical in nature.