Welded steel pipelines that are used to transport oil and gas under high pressure have been known to fail by stress corrosion cracking (SCC), and the cracking can be intergranular, transgranular, or a combination of both, depending on the environmental and operational conditions. In this chapter, the practical aspects of SCC that occurs on the external surfaces of these underground pipelines are discussed, along with preventive measures that can be considered for mitigating failures by SCC.