♦ Objective: We aimed to evaluate the efficacy of acute peritoneal dialysis (PD) and clinical outcomes in neonates with acute kidney injury (AKI) and hypernatremic dehydration. ♦ Methods: The medical records of 15 neonates with AKI and hypernatremic dehydration who were treated with acute PD were reviewed. The diagnoses were AKI with hypernatremic dehydration with or without sepsis in 13 patients and AKI with hypernatremia and congenital nephropathy in 2 patients. The main indications for PD were AKI with some combination of oligoanuria, azotemia, hyperuricemia, and metabolic acidosis unresponsive to initial intensive medical treatment. ♦ Results: The mean age of the patients at dialysis initiation was 11.9 ± 9 days, and the mean duration of PD was 6.36 ± 4.8 days. In 7 patients (46.7%), hypotension required the use of vasopressors, and in 6 patients (40%), mechanical ventilation was required. Peritoneal dialysisrelated complications occurred in 7 patients (46.7%), the most common being catheter malfunction (n = 6). Four episodes of peritonitis occurred in the 15 patients (26.7%), 2 episodes in patients with congenital renal disease and 2 episodes in patients with sepsis and multiorgan failure, who did not survive. Congenital renal disease, septicemia, and the need for mechanical ventilation were important factors influencing patient survival. All patients with no pre-existing renal disease or sepsis recovered their renal function and survived. ♦ Conclusions: In neonates with AKI and hypernatremic dehydration, PD is safe and successful, and in patients without congenital renal disease or sepsis, the prognosis is good. Peritoneal dialysis should be the treatment of choice in neonates with AKI and hypernatremic dehydration who do not respond to appropriate med ical treatment. A cute kidney injury (AKI) in neonates has many causative factors. Hypernatremic dehydration associated with breastfeeding is one such cause. Although successful breastfeeding provides compelling advantages to infants and mothers, inadequate breastfeeding may result in lifethreatening dehydration. Hypernatremic dehydration is a rare complication of breastfeeding (1,2), but recent reports have shown that its incidence is increasing (2-5). Prolonged hypovolemia and decreased renal perfusion can cause intrinsic renal injury.Once intrinsic renal failure becomes established, treatment of the metabolic complications of AKI involves appropriate management of fluid, electrolytes, and acidbase balance; provision of good nutrition; and initiation of renal replacement therapy (RRT) if conventional therapy fails to control metabolic complications and fluid overload (6). The preferential use of hemodialysis (HD) and hemofiltration by pediatric nephrologists is increasing, but those modalities are technically difficult procedures. The large extracorporeal circuit volumes, anticoagulation, and vascular access required are limiting factors, particularly in neonates. As a result, peritoneal dialysis (PD) is generally the most common form of RRT in young child...