This paper addresses on the influence of temperature, elucidated with a number of electrochemical methods and immersion tests, on the corrosion behavior of API-X100 steel in CO2-saturated bicarbonate solutions. Investigated by cyclic potentiodynamic polarization, the corrosion rates, which showed a sensible increase with 10 g L-1 (0.16 mol L-1), 30 g L-1 (0.5 mol L-1) and 50 g L-1 (0.82 mol L-1) bicarbonate concentrations, increased from about 500, to 1500 and 1800 mu A cm(-2) at 20, 50 and 90 degrees C, respectively. Passivation at 50 and 90 degrees C showed resistance to deteriorate against 100 ppm chloride ions, of which anodic 0.5 V vs. SCE peaks exclusively appeared. Moreover, transpassivation occurred at 0.9 and 0.7 V vs. SCE, respectively, unlike with the 20 degrees C cases whose chloride-induced-pitting-vulnerable, gradually-forming passive films transpassivated at 1 V vs. SCE. At different potentials, the potentiostatic currents increased with temperature, but their profiles suggested more effective passivation, accordingly. The charge transfer resistance, calculated by electrochemical impedance spectroscopy, decreased with temperature at the open circuit potentials and 0.6 V vs. SCE, where the interfacial interactions were governed by adsorption, and diffusion-limited processes, respectively. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.