Background: acute kidney injury (AKI) is a common devastating problem in patients complaining of sepsis and septic shock. the deficiency of a slandered consensus definition of AKI make its incidence varies markedly ,the increased incidence of mortality and morbidity in septic patients developing AKI necessitates studying specific biomarkers to diagnosis and assess prognosis and outcome is necessary.  The proximal tubule is the source of kidney injury molecule 1 (KIM-1) which is expressed in case of acute ischaemia. like, acute tubular necrosis. even before serum creatinine rise KIM-1 in urine may be detected after exposure to a many of nephrotoxic agents. Objective: Our aim was to validate that the kidney injury molecule -1 (KIM–1) in urine as a diagnostic and prognostic biomarker in evaluation of preclinical kidney toxicity to facilitate early diagnosis and management of AKI.  Methods: 20 critically ill patients diagnosed with sepsis were included in our study, ten healthy volunteers as a control group. The study was done on patients admitted to the critical care department in Beni-Suef university in the period from February to December 2023. Urine samples were collected from the studied patients on admission day (day 0), 2^nd day of admission (day 2) and 5^th day of admission (day 5), and only once in control group to correlate between KIM 1 levels in patients and control group and to correlate with development of AKI . Results: Our study showed that KIM-1 and creatinine on admission were not significantly correlated in the study group ; (R: 0.123) and p value 0.6. On the other hand KIM-1 on admission and creatinine on day 2 were positively correlated in the study group ; (R: 0.9) with highly significant p value ( 0.0001) and KIM-1 on admission and creatinine on day 5 were positively correlated in the study group ; (R: 0.9) with highly significant p value ( 0.0001 ), KIM-1 on admission at 954pg/ml predicted mortality of the study group with the area under the receiver operating characteristic curve (AUC) 0.96 (sensitivity 87.5% & specificity 84.3 %)with significant p value (0.001). Conclusion: From our study we could suggest that urinary KIM 1 level can be utilized as a good diagnostic and prognostic biomarker for detection of AKI in sepsis