Carbon steel is one of the most common materials used in engineering and industrial applications. The low corrosion resistance of carbon steel in certain environments, such as in marine environments, is one of the major drawback related to its use. The rate of corrosion of steel in salt solution depends on the salt concentration as well as cathode to anode area ratio. In this work, an experimental investigation was performed to study the effect of cathode to anode area ratio on corrosion rate of carbon steel at different concentration sodium chloride (NaCl wt%) solution. Nine Carbon steel samples of known metallurgical composition were used to perform the experiments. All carbon steel samples connected with different area of cupper samples (0.5:1, 1:1, and 2:1). Each couple of steel-copper samples was individually immersed in three groups of plastic vessels filled different chloride concentration solutions (1%, 3% and 5 %) (NaCl wt%). Experimental results showed that a corrosion rate is affected significantly by changing the cathode to anode area ration, where the corrosion rate increases with increasing cathode to anode area ratio. In the addition, the corrosion rate increases with increasing salt concentration up to 3% then it decreases afterward.