This paper reports the synthesis and detailed characterization of silver (Ag)-doped cadmium oxide (Ag-CdO) nanoparticles which were prepared by the facile co-precipitation method. The prepared nanoparticles were characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and diffused reflectance spectroscopy (DRS). Further, the effect of various Ag-doping concentrations on the morphological, structural and optical properties of Ag-doped CdO nanoparticles were also examined and presented in this paper. The XRD results revealed that pure and Ag-doped CdO possess a face-centered cubic (FCC) crystal structure. Importantly, the band gap (Eg) of Ag-doped CdO nanoparticles was examined by diffused reflectance spectroscopy using the Kubelka-Munk method. The optical energy band gap values of Ag-doped CdO nanoparticles with various Ag doping concentrations, i. e. 0,1, 5, 10, 15, 20, 30%, were found to be 1.625, 1.64, 1.73, 1.89, 1.91, 1.93, 1.95 eV, respectively. Interestingly, it was seen that with increasing the Ag concentrations the band gap energies also increases. The present work demonstrates that Ag-doped CdO nanoparticles possess good optical properties and hence present themselves as a potential candidate for various high-technological electronic and optoelectronic devices.