Rare earth metals have been investigated as anti-co rrosion of mild steel in produced water which resul ts during petroleum activity. The techniques utilized in this approach namely “massloss (WL), DC Tafel polarizat ion, AC electrochemical frequency modulation (EFM), AC impe dance spectroscopy (EIS) at25ºC.Iron content (disso lved iron) is measured by spectroscopy and pH values of solutions arerecorded.Data declared that IE% rose w ith addition of rare earth metals and decreased with ra ising temperature. Langmuir’s adsorption isotherm w as the best fit with the revealing data. The thermodynamic acti vation parameters are demonstrated. SEM & EDXtechni ques were employed for surface examination of uninhibite d and inhibited mild steel. The % inhibition demons trated from different methodologieswas in a goodtrend.