The innumerable and compelling benefits of exclusive breastfeeding to the infant, mother, family and society are well recognized. Hypernatremic dehydration is a rare, yet potentially preventable complication of exclusive breastfeeding; the etiology being inadequate lactation. We report 2 exclusively breastfed newborn infants with serum sodium levels of 166 and 159 mEq/L, respectively. Both babies presented with excessive weight loss, fever, dehydration, and irritability. Mothers had inadequate lactation. Corresponding breast milk sodium levels were elevated in both mothers (77 and 45 mEq/l; normal 7-21 mEq/L between 3-14 d postpartum). Appropriate parenteral fluids were administered to correct dehydration and hypernatremia. Serum sodium normalized within 72 hours. Following counseling, breastfeeding was resumed after 48 hours with both the mothers achieving good lactation. Infants were finally discharged on exclusive breastfeeding. Timely recognition and awareness of this potentially lethal, but preventable condition is essential to ensure a favorable outcome.