We aimed to assess the incidence, neurologic and neurodevelopmental outcome of breastfeeding-associated hypernatremic dehydration among hospitalized neonates in rural area of central Turkey. A retrospective study was conducted at Gevher Nesibe Hospital over a 6-year period, to identify otherwise healthy term and near-term (> or = 35 weeks of gestation) breastfed neonates (<29 days of age) who were admitted with serum sodium concentrations of >150 mEq/l and no explanation for hypernatremia other than inadequate milk intake. The incidence of breastfeeding-associated hypernatremic dehydration among hospitalized term and near-term neonates (n = 5592) was 2.1%, occurring for 116 breastfed infants. More than one half of the infants admitted with breastfeeding-associated hypernatremia exhibited abnormal development at 12 or more months of age. Increased efforts are required to establish successful breastfeeding.