AIMS: To determine if there are brain activity differences between paediatric intensive care nurses and allied health professionals during pain intensity rating tasks and test whether these differences are related to the population observed (infant or adult) and professional experience. BACKGROUND: The underestimation of patients’ pain by healthcare professionals has generally been associated with patterns of change in neural response to vicarious pain, notably reduced activation in regions associated with affective sharing and increased activation in regions associated with regulation, compared with controls. Paediatric nurses, however, have recently been found to provide higher estimates of infants’ pain in comparison to allied health controls, suggesting that changes in neural response of this population might be different than other health professionals. DESIGN: Cross-sectional study. METHODS: Functional MRI data were acquired from September 2014-June 2015 and used to compare changes in brain activity in 27 female paediatric care nurses and 24 allied health professionals while rating the pain of infants and adults in a series of video clips. RESULTS: Paediatric nurses rated infant and adult pain higher than allied health professionals, but the two groups’ neural response only differed during observation of infant pain; paediatric nurses mainly showed significantly less activation in the medial prefrontal cortex (linked to cognitive empathy) and in the left anterior insula and inferior frontal cortex (linked to affective sharing). CONCLUSIONS: Patterns of neural activity to vicarious pain may vary across healthcare professions and patient populations and the amount of professional experience might explain part of these differences.