Abstract In this work, the structural, magnetic and magnetocaloric properties of 0.95La_0.45Nd_0.25Sr_0.3MnO₃/0.05CuO composites materials were investigated. The samples have been synthesized by solid-state reaction route. The XRD patterns of composites powders show the presence of both perovskite La_0.45Nd_0.25Sr_0.3MnO₃ and monoclinic Tenorite CuO materials. The microstructural characterization performed using Scanning Electron Microscope shows that copper oxide nanostructure is located in the grains boundaries after pressing. According to the isothermal magnetization measurements around the Curie temperature, the maximum isothermal magnetic entropy change is calculated to be 4.128 J/(Kg.K) at 5 T for the pellet with an interesting enhancement compared to the powder sample 2.7 J/(Kg.K). The relative cooling power is about 212.8 J Kg⁻¹. Resistivity measurements under different magnetic fields were performed in order to investigate the magnetoresistance properties. The obtained magnetocaloric properties show that 0.95La_0.45Nd_0.25Sr_0.3MnO₃/0.05CuO composite was an attractive candidate material for magnetic refrigeration application. About magnetoresistance properties the (% MR) is found to be 32.78% around 320 K under a magnetic field of 5 T.