Background No data on healthcare utilisation and associated costs for the many rare entities of children's interstitial lung diseases (chILD) exist. This paper portrays healthcare utilisation structures among individuals with chILD, provides a pan-European estimate of a 3-month interval per-capita costs and delineates crucial cost drivers. Methods Based on longitudinal healthcare resource utilisation pattern of 445 children included in the Kids Lung Register diagnosed with chILD across 10 European countries, we delineated direct medical and non-medical costs of care per 3-month interval. Country-specific utilisation patterns were assessed with a children-tailored modification of the validated FIMA questionnaire and valued by German unit costs. Costs of care and their drivers were subsequently identified via gamma-distributed generalised linear regression models. Results During the 3 months prior to inclusion into the registry (baseline), the rate of hospital admissions and inpatient days was high. Unadjusted direct medical per capita costs (euro19 818) exceeded indirect (euro1 907) and direct non-medical costs (euro1 125) by far. Country-specific total costs ranged from euro8 713 in Italy to euro28 788 in Poland. Highest expenses were caused by the disease categories 'diffuse parenchymal lung disease (DPLD)-diffuse developmental disorders' (euro45 536) and 'DPLD-unclear in the non-neonate' (euro47 011). During a follow-up time of up to 5 years, direct medical costs dropped, whereas indirect costs and non-medical costs remained stable. Conclusions This is the first prospective, longitudinal study analysing healthcare resource utilisation and costs for chILD across different European countries. Our results indicate that chILD is associated with high utilisation of healthcare services, placing a substantial economic burden on health systems.