The apricot pomace extract (APE) is tested as corrosion inhibitor of steel in neutral solution and in conditions of periodic condensation of moisture imitating atmosphere corrosion of metals via weight loss and electrochemical methods. The highest inhibition efficiency of 96.0% was obtained after about 40 h of exposure to inhibitor-containing electrolyte. The composition of the APE was investigated by using both gas and liquid chromatography-mass spectrometry (GC-MS, LC-MS) analysis. The formation of protecting layer on the mild steel surface was proved by scanning electron microscope (SEM) and atomic force microscope results (AFM).