The improved survival rate of extremely low birth weight(ELBW)infants has resulted in new fluid and electrolyte problems that have not been encountered previously,in particular electrolyte imbalance. ELBW infants are especially vulnerable to hypernatremia(serum sodium value >150 mEq/L). Hypernatremia may be due to rapid dehydration or excessive administration of intravenous fluids(IV)that contain sodium. The current treatment modality for hypernatremia is to increase IV fluids above daily requirements.Enteral sterile water feeds(ESWF)are theorized as an endogenous source of fluids that may decrease elevated electrolytes such as sodium and potassium in premature infants. By giving ESWF to decrease elevated electrolytes, there would be less need for large volumes of IVF that contribute to the co-morbidities of prematurity: bronchopulmonary dysplasia (BPD),intraventricular hemorrhage(IVH)and patent ductus arteriosus(PDA).