Langmuir-Blodgett (LB) monolayers of hexadecyl trimethyl ammonium bromide (HTAB) were deposited onto a carbon steel surface to investigate the inhibition of corrosion by measurement of the polarization resistance and cyclic voltammetry. The corrosion process is efficiently inhibited by the HTAB monolayers in both neutral and acidic media, and the inhibition mechanism is based on the blocking effect with the assistance of the charge effect in acidic environment.