Background Acute kidney injury (AKI) is classically described as abrupt or rapidly reversible reduction of excretion of nitrogenous waste products including urea, nitrogen, and creatinine. In critical care setting, patients with AKI constitute an important subgroup in that they have higher short-term and long-term mortality, prolonged hospital stay, and more resource consumption. Risk factors for AKI in patients with severe illness are multifactorial, including underlying certain predisposing factors, as aged patients tend to acquire AKI more than younger patients, together with underlying comorbidities AKI is common and carries a high mortality rate. Most epidemiological studies were retrospective and were done in Western populations. Aim The aim was to highlight the risk factors, mechanisms, and prognosis in AKI in patients in ICU. Patients and methods This is a prospective, observational study that was carried out in ICU, Benha University Hospitals, from January 2018 to July 2018. This study included 50 critical ill patients admitted to ICU. Oral and written consent was taken from every participant after explaining the procedures of the analysis. All patients were clinically evaluated and had routine assessment. Results The mean age of our studied population was 56.3±6.8 years, demonstrating a significant trend toward an increased number of AKI cases with older age. Males represented 68.9% of the included patients, and 62% of patients with AKI had a history of diabetes mellitus. Mortality was evident in 14% of patients with AKI. Patients with AKI with older age, male sex, diabetes mellitus, chronic obstructive pulmonary disease, congestive heart failure, mechanical ventilation, and vasopressor were significantly associated with renal replacement therapy. Conclusion AKI was associated with high mortality rate, and early identification may cause a dramatic decrease in mortality and morbidity, which could be expected in these high-risk patients.