The corrosion and corrosion inhibition of N80 and P110 carbon steels (CS) in CO2-saturated simulated formation water by rosin amide imidazoline (RAIM) was studied using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results indicate that N80 CS performs better than P110 CS with RAIM at lower temperature and P110 CS at higher temperatures. Inhibition efficiency increased with increase in RAIM concentration and temperature. The data suggest that RAIM functioned as inhibitor via a mixed-inhibitor mechanism and the inhibition process is attributed to the formation of a chemically adsorbed film of RAIM on the surface of the metal via its polycentric adsorption sites. Morphological studies of the carbon steel electrode surface were undertaken by scanning electron microscope (SEM) and atomic force microscopy (AFM).