Background and aim: Acute renal failure (ARF) is defined as an abrupt severe decrease in glomerular filtration rate (GFR). ARF is commonly seen in neonates admitted to neonatal intensive care unit. In this article, we have studied incidence, etiology, predisposing factors, management and mortality in neonates affected by ARF. Methods: A descriptive study was took placed at NICU of Qhaem hospital over a period of one year, between December 2005 and December 2006. 750 neonates were evaluated for ARF, according to having two of three following criteria: 1-oliguria: U/A<1/2cc/kg/h2-BUN>20 mg/dl 3-Cr>1/2 mg/dl Patients were assessed for B.S (blood sugar), BUN, Cr, urine index (FENa, Uosm, BUN/cr, U/P osm, RFI, Una), ABG and kidney sonography. According to patient’s response to the fluid therapy and kidney sonography, they were divided into two pre-renal and renal failure groups. Data were analyzed using descriptive statistics. Result: From 750 neonates admitted in NICU, 38 patients (%5) demonstrated ARF. Pre-renal failure was found in 29 newborns (%76.4) and 9 neonates (%23.6). Predisposing factors for ARF were as following: Asphyxia (%42), Respiratory distress syndrome (RDS) (%26.7), sepsis (%13), sever dehydration (%13) and congenital heart disease (CHD) (%5). Nine infants (%23.6) were died. Mortality was significantly higher in intrinsic renal failure (%88). Conclusion: ARF is still an important etiology of mortality in newborns. Diagnosis of predisposing factors (prematurity, asphyxia, RDS, ventilation and careful kidney control in newborn is essential in this problem.