Nowadays is necessary to have a multidisciplinary approach to the horse, to find the key for the optimal performance not only by considering macronutriens such as protein, fat and sugar, but also minerals such as electrolyte. The electrolytes include minerals such as Sodium (Na), Potassium (K) Chloride (Cl), Calcium (Ca) and Magnesium (Mg), that when dissolved in a appropriate solvent are ionized and conduct an electric current. In the body ions are dissolved in three main compartments: the fluid within the cells, the fluid in the space surrounding the cells, and the blood. They affect many metabolic processes such as the passage of fluid between and within cells (osmosis), the function of the neuromuscular system, the acid-base balance and pH, and the thermoregulatory process. The body maintains the optimal concentration of electrolytes in each compartment by moving electrolytes into or out of the cells. They are very important for the organisms because there is a continues loss from the body and there is no body stores of electrolytes other than those carried in the gastrointestinal tract. This review analyses the main characterized of the most important electrolyte for horses with particular importance for sodium, potassium and chloride. Also calcium and magnesium, even if they are generally considered for its pivotal role in the bone metabolism, are consider as electrolytes present in plasma and extracellular fluids.