The International Classification of Functioning, Disability and Health (ICF) and its version for children and youth, the ICF-CY, can contribute to the knowledge on the lives of young children with cancer, with an international and interdisciplinary language. The main study included questionnaire and interview data from 13 children and their parents connected to a paediatric oncology centre in the West of Sweden. As a first step, an ICF-CY set of codes describing the everyday life situations of the young child with cancer, was developed. As a second step, the 60 previously identified ICF-CY codes were then identified data collected from children and parents in the form of questionnaire or interview at all six data collection time points throughout the study. As a third step, the 30 ICF-CY codes identified in questionnaire items and interview responses were then dichotomised as "no difficulty" for the child or "difficulty for the child".