Abstract LaMn 2− x Fe x Si 2 ( x = 0 , 0.05, 0.10, 0.15, 0.20) compounds were prepared by arc melting. The crystal structure and magnetic properties have been investigated by X-ray diffraction and by using a vibrating sample magnetometer, respectively. The compounds crystallize in the ThCr 2 Si 2 -type structure with the space group I4/mmm. The Curie temperature decreases gradually with the increase of Fe content. The magnetic entropy changes of the compounds, with a field change from 0 to 1.8 T, are derived from the magnetization isotherms at different temperatures. The maximal magnetic entropy change of LaMn 1.9 Fe 0.1 Si 2 reaches 1.72 J/kg K (0–1.8 T) around the Curie temperature near room temperature.