Objectives: On the basis of its safety and accuracy, automation is recommended for parenteral nutrition (PN). The aim of this study was to highlight the changes in practices related to the automation of PN and to perform a cost study comparing manual vs automated production costs. Methods: We conducted a micro-costing study using 1 year of manual production data for adult, neonatal and paediatric PN bagsat a hospital. We used the data to estimate the costs of automating the production process for adult, neonatal and paediatric bags. Results: Major modification to the PN production process resulted in: rationalisation of raw materials, computerisation and optimisation of human needs. Switching from a manual to an automated process reduced the cost of neonatal/paediatric custom bags (€130.73 vs €124.58) and semi-custom bags (€172.08 vs €166.86); but increased the cost of adult bags (€93.06 vs €127.92). Conclusions: The changes resulting from the automation and revision of the production process globally increased annual expenditures by approximately 9.7%. However, automation minimised the risk of misproduction, bag contamination, and led to a more secure production process that reduced risks incurred by the teams. In view of the gain in patient and staff safety (linked to the use of an automated compounding device) the moderate economic impact (<10%) should not deter the automation of PN production circuits.