Background: Given the serious health consequences including vascular complications among type 1 diabetes mellitus (T1DM), circulating ACE2 activity could be used as biomarker for early detection of vascular complication. Objectives: To assess serum levels of circulating ACE 2 among children and adolescents with type 1 diabetes mellitus (T1DM) and evaluate the relation of circulating ACE2 levels to glycemic control and diabetic vascular complications. Patients and methods: This cross-sectional study included 50 children and adolescents with type 1 diabetes mellitus divided equally into 2 groups according to presence or absence of vascular complications. The cases were recruited from attendees of the Pediatrics and Adolescents Diabetes Unit (PADU), Children's Hospital, Ain Shams University, Cairo, Egypt. Cases were compared to 25 healthy age and sex-matched controls. Demographic and anthropometric data, medical history, lipid profile, urinary albumin/creatinine ratio and mean glycated hemoglobin & circulating ACE 2 level were assessted . by Enzyme linked immunosorbent assay (ELISA) technique and Echocardiography was performed by specialized paediatric echocardiographer. Results: Our results revealed significantly higher level of circulating ACE2 in children and adolescents with T1DM compared to healthy control group (p<0.001). Circulating ACE2 level was higher among cases who had neuropathy (p<0.001) and nephropathy (p=0.008), compared to patients without neuropathy and nephropathy, respectively, but ACE2 level did not correlate to HbA1c, lipid profile or albumin/creatinine ratio. Furthermore, it showed significant correlation to right ventricular enlargement and carotid intima-media thickness (CIMT) among complicated cases indicating possible role in cardiovascular and vascular remodeling. Conclusion: Children and adolescents with T1DM have elevated levels of circulating ACE2, particularly when associated with neuropathy or nephropathy, irrespective of their glycemic control. Further research is warranted into the clinical utility of ACE2 as a predictive marker for early detection and management of diabetes-related complications.