INTRODUCTION: Despite centuries of research and clinical work, the diagnosis of diabetes was still treated as a quick death sentence at the beginning of the 20th century. Unfortunately, the number of patients with diabetes is increasing every year. Type 2 diabetes is increasingly common among young people: children and adolescents. The article discusses the type of diabetes and the importance of rapid diagnosis and management. Type 1 diabetes, type 2 diabetes, latent autoimmune diabetes in adults, monogenic diabetes, gestational diabetes were analysed. Life-threatening conditions resulting from complications of diabetes including diabetic ketoacidosis, hyperglycaemic-hyperosmolar state, hypoglycaemia, lactic acidosis were discussed, and the first-line emergency treatment were analysed. The life-threatening complications of diabetes and rescue procedures in these conditions were discussed in detail. CONCLUSIONS: Due to the frequency of life-threatening complications, diabetes is a heavy burden on the medical staff. Adequate diagnosis and implementation of appropriate treatment significantly improve the patient's condition.