📒 Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Their unique size-dependent properties make these materials superior and indispensable in many areas of human activity. Copper-oxide Nano adsorbents are attractive for wastewater treatment for because Nano adsorbents can remove contaminants from wastewater rapidly. In the present work, cupric oxide (CuO) nanoparticles (NPs) were prepared by adopting aqueous precipitation method using copper sulphate 5-hydrate as a precursor and NaOH as a stabilizing agent. This gives a large scale production of CuO-NPs which are utilized for the removal of methylene blue (MB) dye. The CuO NPs were characterized for the studying of their structure and composition from FTIR which reveals the single phase monoclinic structure. The surface morphology of these NPs was carried out by using scanning electron microscopy (SEM). Moreover, the effect of optimization parameters such as time, concentration, dosage and temperature was also examined. Spectrophotometric Technique was used to evaluate the removal of MB in aqueous solution by NPs.