Increased production through the existing facilities together with life extension of ageing assets are the essential integral part of a strategy to address the current low margins. These require suitable materials and corrosion control guidelines to enable improved safety and economy. In this context, optimisation and selection of appropriate materials, which can tolerate H2S , are critical issues. This paper describes the approach necessary to optimise materials for sour service duties and provides respective guidelines focusing on the selection and utilisation of carbon and low alloy steels. It combines laboratory assessment with field experience hence offering effective means of corrosion design for sour service production. Keynotes: Corrosion, Carbon and Low Alloy Steels, Domains of Application, Hydrogen Sulphide Damage, Materials Testing Qualification, Sour Service.