Important long-term health problems have been described after severe paediatric trauma. The International Classification of Functioning (ICF) was developed as a universal framework to describe that health. We evaluated outcome in children after 'severe' trauma (defined as: hospitalised >48 h) by means of a questionnaire based on this ICF construct (IROS). Questionnaires were sent to children; one year after this trauma and to 'control' children without any previous 'severe' trauma. We created propensity score-matched pairs (n=133) and evaluated differences in health perception. IROS characteristics were investigated by means of Item Response Theory models. We then estimated the health state of each individual based on his/her response pattern (factor score z01) and investigated the effect of selected covariates with simple linear regression. Significant odds ratios for differences between matched groups (p<0.05) were observed for among others emotional problems, mobility, societal life and family burden, but not for chronic pain. Children in the trauma group showed, e.g. significant more physician (estimated relative risk R' 1.7) and psychologist (R' 3.5) visits. IROS primarily provides information from medium to high health burden levels and factor scores ranged from 0.41 (lowest) to 0.967 (highest burden). A significant impact on health burden could only be proven for the 'state at discharge' (p=0.015), although there was a tendency towards worse factor scores for children that were older, had a higher Injury Severity Score or after traffic injury. In conclusion, we showed that the burden of health problems for children and families after severe trauma is still high and physical, as well as psychosocial in nature. The health state at discharge seems to predict long-term outcome, which might be of importance in view of, e. g. trajectory assistance. IROS may provide an improved scoring system to evaluate outcome after (paediatric) injury or critical illness.