Abstract. The significance and role of peripheral blood circulation sufficiency in the formation of disorders of the muscular system in children with diabetes mellitus remain insufficiently studied. At the same time, the formation of some chronic complications of diabetes is associated with a deficient muscular system function. Aim of study. To discover the state of blood supply to the lower extremities in children with type 1 diabetes mellitus, according to the ankle-brachial index and to determine the value of deviations in the development of diabetic myopathy. Materials and methods. We examined 137 children with type 1 diabetes mellitus. The control group included 41 apparently healthy children. Assessment of the functional state of skeletal muscles, determination of the skeletal muscle index, hand force index and ankle-brachial index before and after exercise were studied in all patients. The ROC analysis was used to calculate cut-off points for the hand force index and the skeletal muscle index in order to determine the diagnostic criteria for dynapenia and diabetic myopathy. Results. We observed functional disorders of skeletal muscles and a decrease in the skeletal muscle index already in the first year of diabetes mellitus. In dynamics, the progression of violations was noted. Found a negative correlation between the level of glycated hemoglobin and the skeletal muscle index (r = -0.49, p <0.05), and muscle strength (r = -0.31, p <0.05), and a positive correlation with the index percentage of body fat (r = + 0.49, p <0.05). Dinapenia was diagnosed in 68 (49.6%) children with type 1 diabetes mellitus. Diabetic myopathy was established in 37 (27.0%) patients. Changes in skeletal muscles in children with diabetes mellitus were accompanied by a deterioration in peripheral blood supply. This was supported by a decrease in the ankle-brachial index at rest and more significantly after exercise. The worst results were obtained in the group of children with diabetic myopathy. Conclusions.1. We discovered impairment in the functional state of skeletal muscles and a decrease in muscle mass in the form of dynapenia (49.6% of cases) and diabetic myopathy (27.0% of cases) in children with diabetes mellitus, taking into account the increase in the duration of the course of the disease and the insufficient state of glycemic control. 2. Impairment of peripheral circulation is one of the factors in the development of diabetic myopathy in children with type 1 diabetes mellitus. 3. The study of the ankle-brachial index after dosed physical activity can be used to diagnose latent disorders of peripheral blood supply. We can use the definition of the ankle-brachial index as a screening for children with type 1 diabetes mellitus.