Recently, novel materials like gas-sensing metal oxides, mixed metal oxides, and modified mixed metal oxides have attracted great attention owing to their key roles in monitoring environmental pollution, security in hospitals, homes, and public places, and hazardous emissions from industries and automobile exhaust. Initially, the mechanochemical (MCh) method was employed for the synthesis of the CuMnO3catalyst and then the modification of CuMnO3through the hydrothermal route. These synthesized catalysts were characterized by Ultraviolet Violet-Diffused Reflectance (UV-DRS) spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), andScanning Electron Microscopy (SEM).The average particle size obtained for 3 % Fe/CuMnO3was found to be 14–28 nm. The present work proclaimed that among all the synthesized 1,3,5 % Fe/CuMnO3 materials, the 3 % Fe modified CuMnO3material shows significant gas sensing properties towards highly toxic H2S gas released from sewage plants, oil, and natural gas industries, among NH3, CO2,H2S, H2,CO2and Cl2 with moderate temperature requirements and excellent selectivity.