Objectives: Premature birth is associated with a wide range of complications in later life, including structural and functional neurological abnormalities and altered pain sensitivity. We investigated whether during anaesthesia premature-born children display different patterns of background EEG activity and exhibit increased responses to nociceptive stimuli., Methods: We examined background EEG and time-locked responses to clinical cannulation in 45 children (mean age (±SD) at study: 4.9(±3.0)years) under sevoflurane monoanaesthesia maintained at a steady-state end-tidal concentration of 2.5%. 15 were born prematurely (mean gestational age at birth: 29.2 ± 3.9 weeks) and 30 were age-matched term-born children., Results: Background levels of alpha and beta power were significantly lower in the premature-born children compared to term-born controls (p=0.048). Clinical cannulation evoked a significant increase in delta activity (p=0.032), which was not significantly different between the two groups (p=0.44)., Conclusions: The results indicate that whilst under anaesthesia premature-born children display different patterns of background brain activity compared to term-born children., Significance: As electrophysiological techniques are increasingly used by anaesthetists to gauge anaesthetic depth, differences in background levels of electrophysiological brain activity between premature and term-born children may be relevant when considering titration of anaesthetic dose., (Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)