Objective Nutrition societies recommend using standardised parenteral nutrition (SPN) solutions. We designed evidence-based SPN formulations for neonates admitted to our neonatal intensive care unit (NICU) and evaluated their outcomes. Design This was a quality improvement initiative. Data were collected retrospectively before and after the intervention. Setting A tertiary-care level 3 NICU at the Aga Khan University in Karachi, Pakistan. Patients All NICU patients who received individualised PN (IPN) from December 2016 to August 2017 and SPN from October 2017 to June 2018. Interventions A team of neonatologists and nutrition pharmacists collaborated to design two evidence-based SPN solutions for preterm neonates admitted to the NICU. Main outcome measures We recorded mean weight gain velocity from days 7 to 14 of life. The other outcomes were change in weight expressed as z-scores, metabolic abnormalities, PN-associated liver disease (PNALD), length of NICU stay and episodes of sepsis during hospital stay. Results Neonates on SPN had greater rate of change in weight compared with IPN (β=13.40, 95% CI: 12.02 to 14.79) and a smaller decrease in z-scores (p<0.001). Neonates in the SPN group had fewer hyperglycemic episodes (IPN: 37.5%, SPN: 6.2%) (p<0.001), electrolyte abnormalities (IPN: 56.3%, SPN: 21%) (p<0.001), PNALD (IPN: 52.5%, SPN: 18.5%) (p<0.001) and sepsis (IPN: 26%, SPN: 20%) (p<0.05). The median length of stay in NICU was 14.0 (IQR 12.0-21.0) for the IPN and 8.0 (IQR 5.0-13.0) days for the SPN group. Conclusions We found that SPN was associated with shorter NICU stay and greater weight gain. In-house preparation of SPN can be used to address the nutritional needs in resource-limited settings where commercially prepared SPN is not available.