CO2 corrosion of carbon steel is a serious problem in oil and gas production, since most widespread used materials are low alloyed carbon steels. There are many approaches to handle the problem of CO2 corrosion. One flexible and economic way to control corrosion in oil and gas facilities is inhibition but the efficiency of an inhibitor is often limited by flow velocities. To investigate inhibitor efficiency in a superficial flow with high gas velocities no standardized test was available and there were no publications on that topic. So the goal was to do the first investigations in that important field. To attain that goal a special, not standardized flow loop test system has been constructed. Results of these investigations have shown that differences in inhibitor efficiencies are related to chemical composition and flow velocities.