Type 1 diabetes mellitus (T1DM) in children and adolescents is characterized by the autoimmune destruction of pancreatic beta cells, resulting in absolute insulin deficiency. Its onset is typically abrupt, with symptoms such as polyuria, polydipsia, weight loss, and fatigue. Management focuses on maintaining blood glucose levels within target ranges to prevent acute complications like diabetic ketoacidosis (DKA) and long-term complications such as retinopathy and nephropathy. Treatment includes insulin therapy tailored to individual needs, balanced nutrition, regular physical activity, and ongoing blood glucose monitoring. Psychological support and education are crucial for patients and families to manage the challenges of living with T1DM effectively, ensuring optimal growth, development, and quality of life.