Abstract: Corrosion, the oldest problem in oil and gas industry has many factors influencing his growth like temperature, pressure, humidity, mechanical actions and chemicals (CO2, H2S, Organic acid and scales). It can occur locally on the metal surface uniformly or it can be an intergranular attack of equipment. Although the fact that corrosion cannot be totally cured, there exist several methods to prevent or to reduce corrosion rate as cathodic protection, coating, material selection, corrosion inhibitor. Here in this work, we emphasis on the effect of corrosion inhibitor on corrosion rate for that we used water corrosion inhibitor and oil corrosion inhibitor. These inhibitors were either mixed with crude oil or produced water, and spread on metal surface. In this work oil from Western onshore field, India was collected in order to study the effect of corrosion inhibitor on metallic substrates.Keywords: - Corrosion Inhibitor, Water Corrosion Inhibitor, Oil corrosion Inhibitor