Background: Chronic pain is estimated to impact one-in-three children with cerebral palsy (CP). Psychological interventions including behavioral and cognitive strategies play a key role in chronic pain management, but there is a paucity of research exploring their use in children with CP.Aim: To investigate the acceptability and feasibility of biofeedback assisted relaxation training (BART) for chronic pain management in children with CP using a mixedmethods study design.Methods: Biofeedback assisted relaxation training was delivered via BrightHearts, an iOS application. Inclusion criteria were as follows: CP; self-reported chronic pain; age 9-18 years; and fluent English speaker. Children used BrightHearts for ten minutes daily, over four weeks. Qualitative post-intervention interviews were undertaken (child, parent) and quantitative pre-post measures (child) were gathered including pain intensity (numerical rating scale), and anxiety intensity (numerical rating scale).Content analysis was conducted for qualitative data. Descriptive statistics and exploratory analyses were performed for quantitative data.Results: Ten children participated (n = 3 male, mean age = 13.1 years SD = 2.5 years, GMFCS level I = 4, II = 2, III = 3, IV = 1). Predominant movement disorder was spasticity (n = 7) and dyskinesia, mainly dystonia (n = 3). Content analysis suggested an overarching theme "BrightHearts is a good thing to put in my toolbox" providing an overall representation of participants' experiences. For many, BrightHearts was a valuable supplement to children's pain management strategies: "The source of the pain is still there, but the actual effect of the pain isn't so relevant." Four sub-themes were identified: "Managing my pain;" "Managing my anxiety and stress," "Helping me do what I need to do;" and "Fitting it into my life." Some participants reported improvements in their anxiety management, and others described benefits in sleep and school following improved pain/anxiety management. A range of practical and personal factors within this heterogeneous group presented barriers to using BrightHearts including limited time, attention, and boredom. Seven-out-of-eight children would recommendThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.