Background: Hypernatremic dehydration is a serious condition occurring exclusively in neonates. The management is challenging because rapid correction can lead to serious complications. Certain factors like the average environmental temperature play an important role in the frequency of cases detected. Aim: We in the present study tied to evaluate the frequency of hypernatremic dehydration in neonates presenting to our tertiary care hospital. Methods: This Prospective case-control study was conducted in the Department of Neonatology, Aditya Hospital, Hyderabad, from January 2017 to December 2017. A total of n=115 cases__ampersandsigngt;36wks 6 days of gestation age and or 2.499Kg of birth weight, discharged by 36 hours in case of normal vaginal delivery and 72 hrs to 96 hours in lower section cesarean section. With features quite like that of sepsis, neonatal hyperbilirubinemia, but on investigations finally diagnosed and managed as hypernatremic dehydration without sepsis. A total of n=31 cases of hypernatremic dehydration were found out of total n=115 cases in the study. Results: Out of n=31 cases of hypernatremic dehydration, 61.29% were male and 38.7% were females. The average sodium levels throughout the year were estimated in cases with suspicion of dehydration. The sodium levels in the summer months were minimum 159.2 mEq/L and maximum values were 168.1 mEq/L and the average values were 160 mEq/L. Conclusion: The frequency of hypernatremic dehydration is very high in summer seasons in neonates. The typical features of presentation were weight loss, lethargy, hunger, and dehydration. The weight loss was significantly greater in the summer months. Management was done by slow rehydration as per protocol (IV Fluids). Early recognition and prompt treatment will prove beneficial in reducing morbidity and mortality.