Background: Acute renal failure (ARF) is a very common problem in neonatal intensive care unit. Diagnosis of the ARF, as a rule, is established based on serum creatinine, but BUN and creatinine level are indices relatively unsensitive of glomerular function and glomerular filtration rate. Determination of the activity of enzymes allows urine renal pathology diagnosis because renal epithelium is the main source of enzims in urine. The aim of the study conducted on 26 neonates was to establish early diagnosis of the ARF in the urine enzymes with site assessment of renal disease. Material and methods: Descriptive study was conducted in the examination of 26 newborns in the intensive care ward and intensive care newborn ICŞOSMşiC IMSP. Primary ferment urine were collected at 24-48 hours of life in children with creatinine greater than 0.15 mmol / l. USG kidneys - to exclude abnormalities of kidney development. Histological study was performed by the usual method and by applying immunohistochemical reaction using primary monoclonal antibodies. Urine enzymes were determined by biochemical methods using photometric standard reagent kits Diasys (Germany) on StarDast biochemical analyzer (Germany) Results: ARF has largely developed in premature babies (76.9%). The major risk factor for ARF in premature babies is septicemia (65%) and in 100% for term children. Oliguria is characteristic form of ARF for dying children (93.3%). Conclusions: To determine the dynamic process in the kidney and renal disease diagnosis urine enzymes can be used for early diagnosis of ARF.