Pipeline integrity begins with materials selection. For carbon steel pipelines corrosion allowance and corrosion inhibition form the basis for design life achievement. Where this combination is considered to be insufficient corrosion resistant alloys are used. Different operators and national and international standards use different criteria and thresholds to determine whether carbon steel with corrosion allowance or corrosion resistant alloys should be deployed. Differences in corrosion modelling and corrosion inhibitor availability philosophies can lead to carbon steel with minimal corrosion allowance or corrosion resistant alloys being selected for the same field conditions. Even where corrosion resistant alloys are selected factors such as sour service chloride stress cracking exposure to microbes and oxygenated conditions during storage and HISC from cathodic protection can strongly influence the type of CRA selected. Materials selection can also be dominated by mechanical integrity requirements such as strength. This publication examines the various corrosion models and philosophies put forward in different standards and by different operators in the European sector and describes how differing levels of conservatism lead to a wide variation in materials selection. It also examines some of the additional integrity threats that may occur with the selection of corrosion resistance alloys and the methodologies used to mitigate these integrity threats at the design stage.