[en] Structural, magnetic and magnetocaloric properties of Pr_0_._5A_0_._0_5Sr_0_._4_5MnO_3 (A=Na and K) have been investigated. Our samples have been elaborated by the conventional ceramic method at high temperature. X-ray diffraction patterns using Rietveld refinement reveal that our compounds are single phase and crystallize in the orthorhombic structure with Pbnm space group. Magnetization measurements versus temperature under an applied magnetic field of 50 mT indicate that all our investigated samples exhibit a paramagnetic–ferromagnetic transition with decreasing temperature. The values of the Curie temperatures are 270 K and 275 K for A=Na and K, respectively. The magnetocaloric study of a manganite-based composite reveals an enhancement of relative cooling power which is around 67.37% of pure Gd under an applied magnetic field of 5 T.