This paper discusses the clinical and diagnostic principles and methods of treatment of diabetic polyneuropathy, one of the most frequent and complicating diseases in diabetes mellitus. The main stages of diagnosis are discussed, including anamnesis collection, clinical examination, functional tests, and additional studies. Modern approaches to treatment aimed at relieving symptoms and slowing the progression of the disease are also analyzed. The main focus is on glucose control, medication, physical therapy, and lifestyle adjustments. The study aims to improve the diagnosis and effectiveness of treatment of diabetic polyneuropathy, which is important for improving the quality of life of patients.