Electroless Ni-P coating treatment was applied to the mild steel substrate for improving its corrosion resistance. This work aims at studying the corrosion behaviour of Electroless Ni-P deposits were in as-coated state and furnace annealed at various temperatures. The corrosion behaviour of the deposits has been evaluated by potentiodynamic polarization studies in 3.5wt % Sodium Chloride solution. The heat treatment temperatureswere kept at regular intervals to study the corrosion performance of the coatings. The microstructures were analyzed using XRD and a scanning electron microscope used to determine the morphology of the deposits. The results showed that the corrosion and resistance of the mild steel improved after electroless Ni-P coating and the as-coating have higher corrosion resistance than the annealed samples.