This study aims to evaluate the appropriateness of end-of-life care for children with genetic and congenital conditions. This is a decedent cohort study. We used 6 linked, Belgian, routinely collected, population-level databases containing children (1-17) who died with genetic and congenital conditions in Belgium between 2010 and 2017. We measured 22 quality indicators, face-validated using a previously published RAND/UCLA methodology. Appropriateness of care was defined as the overall "expected health benefit" of given healthcare interventions within a healthcare system exceeding expected negative outcomes. In the 8-year study period, 200 children were identified to have died with genetic and congenital conditions. Concerning appropriateness of care, in the last month before death, 79% of children had contact with specialist physicians, 17% had contact with a family physician, and 5% received multidisciplinary care. Palliative care was used by 17% of the children. Concerning inappropriateness of care, 51% of the children received blood drawings in the last week before death, and 29% received diagnostics and monitoring (2 or more magnetic resonance imaging scans, computed tomography scans, or X-rays) in the last month. Conclusion: Findings suggest end-of-life care could be improved in terms of palliative care, contact with a family physician and paramedics, and diagnostics and monitoring in the form of imaging. What is Known: • Previous studies suggest that end-of life care for children with genetic and congenital conditions may be subject to issues with bereavement, psychological concerns for child and family, financial cost at the end of life, decision-making when using technological interventions, availability and coordination of services, and palliative care provision. Bereaved parents of children with genetic and congenital conditions have previously evaluated end-of-life care as poor or fair, and some have reported that their children suffered a lot to a great deal at the end of life. • However, no peer-reviewed population-level quality evaluation of end-of-life care for this population is currently present. What is New: • This study provides an evaluation of the appropriateness of end-of-life care for children who died in Belgium with genetic and congenital conditions between 2010 and 2017, using administrative healthcare data and validated quality indicators. The concept of appropriateness is denoted as relative and indicative within the study, not as a definitive judgement. • Our study suggests improvements in end-of-life care may be possible, for instance, in terms of the provision of palliative care, contact with care providers next to the specialist physician, and diagnostics and monitoring in terms of imaging (e.g., magnetic resonance imaging, computed tomography scans). Further empirical research is necessary, for instance, into unforeseen and foreseen end-of-life trajectories, to make definitive conclusions about appropriateness of care.