The inhibition effect of Seaweed extract on the corrosion of mild carbon steel in saline formation water was studied by weight loss, polarization and electrochemical impedance spectroscopy (EIS) methods. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) examinations of the electrode surface have also been carried out. The effect of Seaweed extract on the corrosion rate was determined at various temperatures and concentrations. The inhibition efficiency increases with the increase in Seaweed extract concentration but decreases with the rise in temperature. The adsorption of constituents of Seaweed extract obeyed the Temkin adsorption isotherm. Polarization results revealed that Seaweed extract suppresses the anodic reaction. The kinetic parameters of the corrosion process were evaluated and discussed. (C) 2016 Elsevier B.V. All rights reserved.