Background: Sepsis is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. Acute kidney injury (AKI), previously called acute renal failure (ARF) is an abrupt loss of kidney function, Generally it occurs because of damage to the kidney tissue caused by decreased kidney blood flow (Kidney ischemia) from any cause. AKI may lead to a number of complications, including metabolic acidosis, high potassium levels, uremia, changes in body fluid balance, and effects on other organ systems, including death. Aim: The aim of the study is to show the incidence and prognosis of acute renal failure in patients with sepsis and septic shock. Patients and methods: This prospective randomized study was conducted on patients who were admitted to ICU in Ain Shams University Hospitals. Forty patients were included in this study and an informed written consent was obtained from patients and/or relatives. All patients were adult, more than 18 years old, admitted to ICU suffering from severe sepsis or had septic shock for monitoring, management and follow up to their condition in period of six months. All patients were more than 18 years old that were critically ill either in severe sepsis or had septic shock. We excluded patients less than 18 years old, patient or relatives who refused to be included in this study, and if he/she has a history of previous kidney troubles or dysfunction. All patients were subjected to assessment of the demographic data of the patient, causes and site of infection, pathogenic bacteria as declared by different cultures, APACHE 2 score on admission, all patients were managed as declared by ICU, protocol for septic patients, hemodynamic monitoring was done daily, routine lab investigation daily, coagulation profile had to be done on days 0, 3, 7 of admission, SOFA score on days 0, 3, 7 of admission, renal functions include blood urea and creatinine clearance test had to be done daily, any deterioration of renal function was reported, and if the patient was in need for renal replacement therapy or dialysis, this would be reported. Results: Forty patients were included in this study, their ages with a mean of 58.37 ± 15.66 years. 23 patients (57.5%) were males and 17 patients (42.5%) were females. The most frequent risk factors were hypertension (62.5%) followed by diabetes (52.5%). The incidence of AKI was 60% of patients and the need for renal replacement therapy (RRT) was 9 (22.5%). Outcome of admitted patients in ICU was 23 (57.5%) survived patients and 17 (42.5%) non-survived patients. The study showed that there were no statistical significant differences between AKI and Non-AKI patients except for; gender (male), BMI, gram –ve bacterial infection, creatinine, BUN, creatinine clearance, history of ACE administration, use of vasopressors, APACHE II score at admission and mortality were statistically significant (p < 0.05). Conclusion: The incidence of AKI was 60% of patients in our study. The development of septic AKI adversely affected clinical outcomes. Moreover, the severity of AKI was associated with increased short-term mortality as observed in ICU patients. The study showed that there were no statistical significant differences between AKI and Non-AKI patients except for; gender (male), BMI, gram –ve bacterial infection, creatinine, BUN, creatinine clearance, history of ACE administration, use of vasopressors, APACHE II score at admission and mortality were statistically significant (p < 0.05).