To evaluate the status quo of type 1 diabetes (T1D) management and characteristics of hospitalised patients with T1D in China through a nationwide multicentre registry study, the China Diabetes Type 1 Study (CD1S).Clinical data from the electronic hospital records of all people with T1D were retrospectively collected in 13 tertiary hospitals across 7 regions of China from January 2016 to December 2021. Patients were defined as newly diagnosed who received a diagnosis of diabetes for less than 3 months.Among the 4993 people with T1D, the median age (range) at diagnosis was 23.0 (1.0-87.0) years and the median disease duration was 2.0 years. The median haemoglobin A1c (HbA1c) level was 10.7%. The prevalence of obesity, overweight, dyslipidemia, and hypertension were 2.5%, 10.8%, 62.5% and 25.9%, respectively. The incidence rate of diabetic ketoacidosis at disease onset was 41.1%, with the highest in children <10 years of age (50.6%). In patients not newly diagnosed, 60.7% were diagnosed with at least one chronic diabetic complication, with the highest proportion (45.3%) of diabetic peripheral neuropathy. Chronic complications were detected in 79.2% of people with T1D duration ≥10 years.In the most recent years, there were still unsatisfactory metabolic control and high incidence of diabetic ketoacidosis as well as chronic diabetic complications among inpatients with T1D in China. The ongoing CD1S prospective study aims to improve the quality of T1D management nationally.© 2024 John Wiley & Sons Ltd.