Polyamide- 11 has been used for more than twenty years as the chemical and pressure barrier in flexible pipes used in off-shore oil and gas production. Recently, polyamide-11 has been used to line and protect carbon steel pipelines carrying corrosive sour raw gas and condensates. The liner was inserted in the field using the well-known roller-box diameter reduction technique. It is being used successfully at temperatures that are not possible with conventional polyethylene liners. Until now, at temperatures above about 45°C only corrosion inhibition programs have proven to be effective in controlling the internal corrosion rates of carbon steel pipes carrying sour raw gas. There is a total of about six kilomers of polyamide-11 now installed in five pipelines located in central and northwestern Alberta, Canada, and operating at temperatures up to about 80°C. The installations and the properties of exposed and aged polyamide- 11 liner are discussed. The chemical resistance and mechanical properties of the polyamide-11 that make this application possible are discussed in detail.