In thin work. the corrosion behavior of iron and aluminum was investigated in 0.1 M NaCl solutions with an initial pH value of 8 and containing various concentrations (0. 30, 150 300 ppm) of benzoic acid. For this purpose, the anodic and cathodic semilugarithmic current-potential curves. weight loss and pH of the solution were determined over time, The changes in the concentrations of benzoic acid in the solutions with time were determined by a UV spectrophotometer. According to the results obtained in this investigation. benzoic acid in 0.1 NI NaCl acts on iron and aluminum as an inhibitor. This effect gets stronger with increasing concentrations of benzoic acid in 0.1 M NaCl solution.