In the present study we report the effect of K doping on the structural, magnetic and magnetocaloric properties in La 0.8 Ag 0.2−x K x MnO 3 (0≤x≤0.15) powder samples synthesized using the solid state reaction method at high temperature. X-ray diffraction analysis using Rietveld refinement show that all our samples crystallize in the rhombohedral structure with R3¯c space group. The surface morphology and elemental analysis of both samples were carried out by scanning electron microscopy (SEM) and energy dispersive X-ray technique (EDX), respectively. Magnetization measurements versus temperature in a magnetic applied field of 50mT showed that all our investigated samples display a paramagnetic–ferromagnetic transition with decreasing temperature. The Curie temperature T C increases with increasing K content from 278.5K for x=0–330K for x=0.15. A large magnetic entropy change |ΔS M |, deduced from isothermal magnetization curves, has been observed in our samples with a peak centered around their respective T C . The maximum of the magnetic entropy change |ΔSMMax| in a magnetic field change of 5T is found to be 6.12, 5.28, 4.92 and 4.26Jkg −1 K −1 for x=0, 0.05, 0.1 and 0.15 respectively. Large relative cooling power (RCP) value of 258.3Jkg −1 is obtained for La 0.8 Ag 0.05 K 0.15 MnO 3 sample, at a field change of 5T. This relatively large value associated to a Curie temperature of 330K make the present compound a promising candidate formagneticrefrigerators around room temperature.