Aims: To explore the meanings that parents and children attach to food and eating, and how these influence their approaches to dietary management of cystic fibrosis (CF). Methods: Ethnographic design using in-depth interviews with 32 children with CF (aged 6-14 years) and their parents, and participant observations during visits to CF clinics with a sub-group of 21 children. Data were analysed using the constant comparative method and theoretical sampling was used to further explore and develop emergent themes. Results: Dietary management was found to be a demanding task for children and their parents, and priorities differed between them. A priority of feeding for parents was to protect their children's long term physical health and survival by keeping their weight up. A challenge for parents was to ensure their children's cooperation with eating. A priority for children in being healthy was to have energy for physical activities and so energy rather than weight was of immediate relevance to their daily lives. These differences between parents and children gave rise to tensions and conflicts in their interactions with one another in managing diet. Conclusions: Healthcare professionals should take account of the meanings that children and their parents attach to food and eating that can influence their decisions about implementing CF dietary recommendations. The role of children in making food choices has implications for acknowledging them as active participants in their dietary care and for adopting child centred approaches to dietary advice for CF.