AIM:To assess the best energy intake in Parenteral Nutrition (PN) for preterm newborns, considering both possible benefits for growth and risk of complications. METHODS:Quasi-experimental study comparing two cohorts of newborns, receiving Energy-Enhanced vs. Standard PN (Cohort A, from 1st January 2015 to 31 January 2016 and Cohort B from 1st February 2016 to 31 March 2017; respectively) after implementation of a change in the PN protocol. The primary outcome measure was growth at 24 months of life. The PN associated complications were also measured. RESULTS:We enrolled 132 newborns in two Cohorts, similar for prenatal and postnatal clinical characteristics. Although, body weight and length at 24 months of life were significantly higher (p