Introduction Serum creatinine is a late marker of acute kidney injury (AKI) and its alterations are often not apparent until 48–72 h postinjury. Urine and plasma neutrophil gelatinase associated lipocalin (NGAL) measurements may represent early biomarker of AKI in intensive care, being able to predict this complication ∼2 days prior to the rise in serum creatinine. Aim To evaluate the role of plasma NGAL level as a marker for early diagnosis of AKI in ICU patients and if it is related to the severity of kidney injury and renal outcomes. Patients and methods Our study including 40 ICU patients, 20 patients admitted for surgical causes and 20 admitted for medical causes. For all participants, clinical examination, laboratory investigations were done in the form of serum creatinine, plasma NGAL, with daily measurement of urine output and estimation of glomerular filtration rate. Patients with AKI were classified according to Risk, Injury, Failure, Loss, End stage renal disease (RIFLE) classification, non-AKI patients served as controls for comparison. Results Out of 40 patients, 14 (35%) developed AKI, and according to RIFLE classification, seven (17.5%) were class R, four (10%) were class I, three (7.5%) were F. There was statistically significant comparison between operative time and development of AKI in surgical patients. Also patients who did not develop AKI had lowest NGAL level while AKI group showed rising level with RIFLE classes. Conclusion Plasma NGAL can be used as early biomarker for diagnosis of AKI and its level is increasing with the severity of AKI classes in ICU patients