Background Neonatal Intensive Care (NICU) patients have individual nutritional requirements often requiring Patient Specific Parenteral Nutrition (PSPN). From October 2015, the national PSPN compounding service availability changed from 7 days per week service to 5 days per week (i.e. no weekend and limited bank holiday ordering available). The aim of this study was to examine the introduction of a 5 day only PSPN supply on neonatal patient parenteral nutrition availability in a tertiary NICU. Methods We performed a prospective assessment of the provision of a 5 day rather than 7 day ordering of PSPN over a one month period (June 2017). Results Fifteen neonatal patients received a cumulative 89 days of PN during June 2017. 10 (66%) patients received PSPN during this time period. There was same day availability of PSPN in 62 of 89 days of PN (69%). Conclusion Thorough education and training will help prescribers to make appropriate PSPN ordering decisions. Improvements to available stock bags may reduce the amount of PSPN that is required but a 7 day PSPN ordering service would improve efficient provision of clinically indicated PSPN to premature infants in NICU in Ireland.