The inhibition performance of thiobenzamide (TB) against the under-deposit corrosion of carbon steel in CO 2-saturated, chloride-containing environment has been investigated. TB concentrations were varied from 10–200 ppm and temperatures from 30 C to 60 C were tested. TB effectively inhibits corrosion at carbon steel surfaces with and without sand deposits, reducing the general corrosion rates below 0.1 mm y− 1 in all cases studied. Electrochemical test results suggest that inhibition occurs via adsorption at the steel surface through the S atom of the TB molecule. Potentiodynamic polarization measurements show that the inhibition mechanism differs at surfaces with and without sand deposits with temperature change over the range of 30 C to 60 C. Surface analysis of the corroded steels showed that general corrosion takes place at surfaces without sand deposits, whereas localized corrosion proceeds at the surfaces underneath a sand deposit, both in the presence and absence of thiobenzamide.