Aim: To determine the extent of unlicensed and off-label drugs prescribed in a neonatal unit at a University Hospital, Lyon, France. Methods: We conducted a prospective cohort study of newborns who were admitted to the neonatal unit in France during a 4 month-period (from January 1st to April 30th 2009). Using French primary reference source (Vidal 2009), all drug prescriptions were assessed to determine the extent of unlicensed or off-label use. Results: A total of 65 newborns, 55 preterm and 10 full-terms were admitted to the neonatal ward and received 265 prescriptions. Fifty four percent (143/265) of prescribed drugs were licensed, 16.6% (44/265) were off-label for paediatric use, 21% (56/265) for age, 2.4% (6/265) for dosage and 6% (16/265) for route of administration. Unlicensed drug utilisation has not been detected. Seventy one percent (46/65) of infants received at least one offlabel prescription. Conclusion: Prescriptions of off-label drugs in neonatal unit is common. Clinical trials assessing the benefit and harms of off-label or unlicensed drugs frequently prescribed should improve the lack of trial-based data for children.