Material loss due to CO2 corrosion can be limiting factor for the use of carbon steels in pipelines for unprocessed hydrocarbons. In many subsea projects the pipeline costs are a considerable part of the investment and the economical impact of improved understanding and control of the CO2 corrosion of carbon steel is large. This report summarizes the effect of the most important parameters on CO2 corrosion, and gives an overview of corrosion. Fields in the Norwegian part of the North Sea are used as examples. New and untraditional methods for significant reduction of corrosivity in gas/condensate pipelines are briefly mentioned. The report concludes with a discussion on how these problems may be handled in future long distance transport lines for unprocessed hydrocarbons.