Significant efforts have been made to improve the nutritional support of preterm infants in neonatal intensive care units (NICUs) to avoid cumulative nutritional deficits, reduce postnatal growth restriction, and promote optimal long-term development. The objective of this systematic review was to compare the characteristics and results of all surveys published in the past 10 y (2002-2012) that used a questionnaire to survey at least 2 NICUs receiving preterm infants with an intention to treat with parenteral nutrition (PN) and that reported information on at least 1 macronutrient. A total of 6 surveys were identified, which were conducted in the United States (n = 2) or Europe (n = 4). There was wide variability in the response rate (23-100%), with a higher response rate in the smaller studies (81-100%; 8-64 respondents) compared with the larger studies (23-58%; 296-809 respondents). Large differences were observed in the nutritional protocols both among the NICUs in the individual surveys and between surveys. PN was initiated on the first day of life (DOL) by only 24-54% of respondents (4 surveys) and within the second DOL by 67-94% of respondents (5 surveys). Lipids were initiated before the third DOL for 46-96% of respondents (3 surveys). The results of this systematic review suggest that continuous education is needed and that greater efforts are required to disseminate and implement guidelines. Repeated surveys are needed to highlight trends in clinical practices and level of compliance of NICUs with existing guidelines.