To determine the incidence of hospitalisation for all diagnoses among Australian youth with type 1 diabetes.We linked Australians aged under 20 years with type 1 diabetes on the National Diabetes Services Scheme (n = 45,685) to hospital admission data from 2010 to 2019. We determined relative risks (RR) of hospitalisation among those with type 1 diabetes in the states of Victoria and Queensland (n = 21,898) compared to the general population for 2010-2017 using Poisson regression.Australian youth with type 1 diabetes had increased risk for almost all reasons for hospitalisation compared to the general population, especially infections such as anogenital herpesviral infections (RR 54.83, 95% CI 33.21-90.53), and mental health disorders including personality disorders (RR 9.70, 95% CI 8.02-11.72). Among those with type 1 diabetes, over 60% of hospitalisations were directly related to diabetes, almost half of which were for ketoacidosis. Approximately 15% of ketoacidosis admissions occurred within 3 months of diabetes diagnosis. One quarter of those with admissions for ketoacidosis were readmitted for ketoacidosis within 12 months. Residence in areas of high socio-economic disadvantage was an independent risk factor for admission and readmission for ketoacidosis.Youth with type 1 diabetes are susceptible to a wide range of complications. Clinicians should consider screening and prevention for conditions such as infections and mental health disorders. Targeted support and education around glycaemic management should be considered in those at high risk for ketoacidosis admission including those living in areas of high socio-economic disadvantage.