Corrosion of carbon steel weldments can be due to metallurgical effects, such as preferential corrosion of the heat-affected zone (HAZ) or weld metal, or it can be associated with geometrical aspects, such as stress concentration at the weld toe, or creation of crevices due to joint design. This article describes the issues related to corrosion of carbon steel weldments and the remedial measures that have proven to be successful in specific cases. It provides useful information on preferential HAZ corrosion, preferential weld metal corrosion, and galvanic corrosion.