The application of Carum Carvi’s essential oil in a corrosion inhibitor for mild steel (MS) protection was investigated in 1 M HCl solution. Essential oil from Carum Carvi was obtained by Clevenger type water distillation. The major compounds in these essential oils was identified using gas chromatography-mass Spectrometry: Apiol dill (15,6%), Limonene (15,3%), Carvone (13,3 %) and p-Cymene (11,3%). The electrochemical impedance spectroscopy and potentiodynamic measurements were used at various concentrations and temperatures. The oil acted  as  an efficient  inhibitor  against  the  carbon  steel  corrosion  in  1  M  HCl,  and  its  inhibition  efficiency  increased with  the  inhibitor  concentration  reaching  a  value  of  up  to  88%  at  3  g/L.  Polarization studies showed that the oil was a mixed-type inhibitor.  Adsorption  of  oil  on  the  steel  surface  in  1  M  HCl  solution followed  Langmuir’s  isotherm  and  the  thermodynamic  parameters  were  determined  and  discussed