Purpose: We aimed to evaluate the incidence and identify risk factors for acute kidney injury (AKI) within the first 15 days of life in very low birth weight (VLBW) infants in a neonatal intensive care unit. Additionally, we examined whether AKI correlates with increased mortality rate in this population. Methods: A prospective analysis was conducted on VLBW infants admitted to the neonatal intensive care unit from March 2017 to July 2021, diagnosing AKI based on the neonatal modified Kidney Disease: Improving Global Outcomes criteria. Neonates who died before obtaining consent, had complex malformation, or only one serum creatinine measurement were excluded. Results: Out of 121 admitted VLBW infants, 97 were analyzed, with 20 (20.6%; 95% confidence interval, 12.6-28.7) diagnosed with AKI. Among these, 50% had creatinine abnormalities, 30% had urinary output changes, and 20% had both. Severe AKI (stage 2 or 3) was observed in 30% of cases, none required dialysis. AKI was associated with higher SNAPPE-II (Score for Neonatal Acute Physiology with Perinatal Extension-II) scores, more frequent severe intraventricular hemorrhage, and an increased mortality rate (35%). Multivariate analysis identified AKI as an independent risk factor for mortality, with a 9.72-fold increased risk (95% confidence interval, 2.53-37.4; P<0.01), and a shorter time to death. Conclusions: Our findings underscore a significant incidence of AKI among VLBW infants, along with its strong association with increased mortality. These results highlight the critical need for thorough assessment of both serum creatinine and urinary output when diagnosing AKI in this vulnerable population.