Acute kidney injury (AKI) is an important contributing factor to the morbidity and mortality of critically ill neonates. Neonates with respiratory distress syndrome (RDS) are at increased risk of AKI due to exposure to hypoxia, acidosis, hypovolemia, vasopressors and mechanical, the aim of the study is to compare serum cystatin C levels (sCysC) in preterm neonates with respiratory distress syndrome (RDS) with a control group and to evaluate the role of serum cystatin c in prediction of acute kidney injury in preterm with RDS a prospective study (case-control) Conveyed crazy from february 2019 on january 2020. The contemplate might have been led on 62 neonates starting with the neonatal emergency unit units (NICUs) about Benha college healing centers Furthermore Benha protection Hospital, might have been subdivided into; one assembly (I): Which incorporated 34healthy control preterm neonates without RDS ,Group (II): Which included 22 preterm neonates with RDS without AKI Furthermore one assembly (III): Which incorporated 6 preterm neonates with RDS & AKI, there were six neonates with AKI and 22 neonates without AKI Throughout those 1st 7 days In view of KDIGO definition about AKI, sCysC levels at 3rd day about life were essentially higher over neonates with RDS Be that as no AKI and neonates in the control group, serum creatinine (sCr) qualities during 3rd day about an aggregation demonstrated no noteworthy distinction the middle of the individuals with RDS for AKI, RDS What's more no AKI or control groups, sCysC could be utilized as a free predictor of AKI for preterm neonates with RDS.