Since 2008 all Belgian paediatric diabetes centres (PDCs) participate to a biennial audit/feedback, allowing to monitor the quality of care given in PDCs and to describe clinical and demographic characteristics of young patients (≤18 years) with type 1 diabetes (T1D) on a national level. Here we present the evolution of the hemoglobin A1c (HbA1c) between 2008 and 2019 and investigate the determinants of HbA1c among children and adolescents with T1D.