Material and methods: Observational, retrospective study including post-surgical critically ill patients admitted to the post-surgical reanimation unit (RU) in whom PN was prescribed, in 2011. Demographical, anthropometric, diagnosis, nutritional parameters, mortality, total duration of hospitalization and duration of hospitalization at the RU, and complications were gathered. The type of PN prescribed was compared, with individualization of the requirements by Kg of body weight, according to the latest recommendations published on nutrition of critically ill patients (ASPEN, ESPEN, SENPE): 18-30 kcal/kg, 0.8-1.5 g/kg/proteins, 4 mg/kg/min/glucose and 2-3 mg/kg/min/glucose in patients with stress-related hyperglycemia, and 0.5-1 g/kg/day of lipids. The variables analyzed were caloric, protein, and glucose adjustments in the initial PN, recovering of albumin > 3 g/dL at day 10, and likely association with the number of complications, mortality and hospital stay.