In the last few years, copper and copper oxide nanoparticles were involved in many applications; this encouraged many researchers worldwide to develop more facile synthesis methods. Unprecedentedly, the current study reports a green method for synthesizing copper/copper oxide nanoparticles (Cu/Cu 2 O NPs) using the extract of seedless dates. Cu/Cu 2 O NPs were synthesized according to the chemical reduction method using seedless dates' extract as a reducing agent due to its high content of phenolics and flavonoids. Transmission Electron Microscopy (TEM) revealed that roughly spherical particles were synthesized. Dynamic Light Scattering (DLS) showed that the synthesized Cu/Cu 2 O NPs have an average particle size of 78 nm and zeta potential of þ41 mV, indicating a good stability of the particles. Successful synthesis of Cu/Cu 2 O NPs was affirmed through both X-Ray Diffraction (XRD), which revealed the presence of the characteristic peaks of copper at 2θ ¼ 43.2745, 50.4083 and 74.1706 , and UV-Vis. Spectroscopy, which revealed the surface plasmonic resonance peak characterizes Cu/Cu 2 O NPs at 576 nm. In addition, Fourier Transform Infrared Spectroscopy (FTIR) revealed the presence of phenolic compounds, which were responsible for reducing copper ions into copper nanoparticles through their carbonyl and hydroxyl linkages, adsorbed from the extract on Cu/Cu 2 O NPs. Conclusively, the current work provides, for the first time, a simple, cost-effective and environmentally friendly method for synthesizing Cu/Cu 2 O NPs using useless seedless dates.