This study was conducted in the neonatal intensive care unit of Benha University Hospital, Egypt from 1 August 2012 to the 31 January 2013 to identify medical errors and to determine the risk factors and consequences of these errors. Errors were detected by follow-up of neonates and review of reports including nursing followup sheets, resident progression notes and investigation reports. We detected 3819 errors that affected 97% of neonates. Types of errors included 403 medication errors (10.55% of total errors), 652 errors in daily routine procedures (17.07%), 1042 errors in invasive procedures (27.28%), 68 errors in nutrition (1.78%), 63 equipment errors (1.64%), 260 administration errors (6.8%), 656 staffing errors (17.18%), 107 environmental errors (2.8%), 448 infection control errors (11.73%) and 120 nosocomial infection errors (3.14%). Medical errors were high in low birth weight, low gestational age neonates and increased with duration of admission.