This paper presents the experimental results for CO2 corrosion of C-1018 carbon steel in a multiphase flow system using electrochemical noise measurement. A unique biased ZRA mode electrochemical noise technique is utilized to study the corrosion processes and detect localized corrosion preferentially on a single electrode due to external polarization of the bias voltage under extended exposure times. For full pipe flow at 0.55 m/s liquid velocity, the experimental results show that both noise resistance Rn and noise impedance Rosn can be related to the corrosion activity. The trends of Rn and Rosn at different experimental times are also consistent with the results obtained from EIS experiments. The experimental results at slug flow of Froude Numbers of 6 and 9 show that the magnitude of current noise increases with the increase of flow turbulence, Compared to slug flow, the current noise fluctuation for full pipe flow is much lower. © 2000 by NACE International.