Parenteral nutrition (PN) is a standard of care for preterm infants in the first postnatal days. The European Society of Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) has updated their guideline recommendations on PN in 2018. However, data on actual 2018 guideline adherence in clinical practice are sparse. In this retrospective study, conducted at the neonatal intensive care unit (NICU) of Ghent University Hospital, we analyzed the ESPGHAN 2018 PN guideline adherence and growth for 86 neonates admitted to the NICU. Analyses were stratified by birth weight (<1000 g, 1000 to <1500 g, ≥1500 g). We documented the provisions for enteral nutrition (EN) and PN, and we tested the combined EN and PN provisions for ESPGHAN 2018 adherence. The nutrition protocols showed a high adherence to PN guidelines in terms of carbohydrate provisions, yet lipid provisions for EN and PN often exceeded the recommended maximum of 4 g/kg/d; although, PN lipid intakes maxed out at 3.6 g/kg/d. Protein provisions tended to fall below the recommended minimum of 2.5 g/kg/d for preterm infants and 1.5 g/kg/d for term neonates. The energy provisions also tended to fall below the minimum recommendations, especially for neonates with a birth weight (BW) < 1000 g. Over a mean PN duration of 17.1 ± 11.4 d, the median weekly Fenton Z-scores changes for length, weight, and head circumference were positive for all BW groups. Future studies have to assess how protocols adapt to current guidelines, and how this affects short- and long-term growth across different BW groups. In conclusion, the reported findings provide real-world evidence regarding the effect of ESPGHAN 2018 PN guideline adherence, and they demonstrate how standardized neonatal PN solutions can safeguard stable growth during NICU stays.