Kidney injury (KI) is a major contributor toward infants mortality and morbidity and is associated with greater long-term risk of chronic kidney disease.The current diagnostic approach of KI is based on an acute decrease of GFR, as reflected by an acute rise in serum creatinine (SCr) levels and/or a decline in  urine output over a given time interval, Recently several biomarkers have been proposed for the diagnosis of KI and these are in various stages of development and validation. to evaluate kidney injury molecule (KIM) as an early urinary marker for prediction of acute renal injury in infants.a comparative cross sectional study was performed on 2 groups: cases group included 30 critically ill infants who were suffering from a variety of critical conditions with mean age 6±2.1 months, their sex distribution was 40% males and 60% females. Another group (control group) of 20 healthy control subjects matched  the first group in age and gender. The time period of this study was between august 2016 to august 2017. All patients were subjected to complete maternal history taking, full clinical examination and laboratory investigations including CBC, CRP, Na, K, cord PH, Urea and serum creatinine were measured since the first 24hrs (1st sample) of admission and serum creatinine was repeated after 48 h of admission (2nd sample). Critically ill infants were sub sequently discriminated ,within 48 hour of admission ,according to the criteria proposed by the AKIN ,into neonates with KI (group 1A) and infants without KI (group 1 B) , Comparative data were collected between first and second samples of hematologic investigations, renal functions , Na, K, cord pH, CRP and  blood culture growth in  all studied critically ill infants, cases without KI and cases with AK.  Another comparison of  KIM, creatinine was done between first and second samples in  all studied critically ill infants , with KI and without KI. It was revealed predominance of female sex with no significant difference between groups of the study regarding age, length, and weight. No significant differences were found in hematologic investigations, renal functions, Na, K  or blood culture growth at diagnosis between cases and controls as well as between critically ill infants with and without KI. It was reported significant change in creatinine level in second sample between KI patients and patients without KI and also it was revealed significant increase in KIM concentration in first sample.  As well as  KIM level was significantly higher in second when compared to first sample in critically ill patients with KI. KIM is a sensitive urinary biomarker in early detection of KI in infants.