The significant roles played by sodium and chloride in the study of livestock nutrition as well as the interaction of both minerals with potassium was highlighted in this chapter. Other topics discussed include: dietary sources of sodium and chloride, metabolism of sodium and chloride, functions of sodium and chloride, biological and physiological manifestation of sodium deficiency, clinical manifestations of sodium deprivation, occurrence of sodium deprivation, the diagnosis of sodium deprivation, prevention of sodium deficiency, sodium requirements, sodium and salt toxicity, deficiency of chloride, signs of chloride deficiency, chloride requirements, and chloride toxicity.