Diabetes mellitus is a longterm metabolic condition characterized by hyperglycemia and a disorder of carbohydrate, fat and protein metabolism. There are multiple types of diabetes: type 1 diabetes mellitus, type 2 diabetes mellitus, gestational diabetes, and other specific types of diabetes. The number of people with diabetes is rising constantly, both in Croatia and worldwide. It is estimated that 9.3 % of the world’s population is currently affected by diabetes, whereas in Croatia the number of registered persons with diabetes in 2018. was 303 992. Type 1 diabetes mellitus is treated with insulin therapy and type 2 diabetes mellitus is treated with oral medications and in cases of insufficient β-cell secretion of insulin, insulin injections may be necessary. In both types of diabetes, it is important to make lifestyle changes that include a healthy diet and regular exercise. One of the most serious complications of insulin therapy and oral medications is hypoglycemia. Hypoglycemia is a plasma glucose concentration low enough to cause signs and symptoms. Symptoms caused by hypoglycemia can be divided into two categories: neuroglycopenic and neurogenic symptoms. The incidence of severe hypoglycemia in type 2 diabetes is lower than in type 1 diabetes, but since type 2 diabetes is ten times more common than type 1, hypoglycemia in type 2 diabetes presents a greater clinical problem. Causes of hypoglycemia in diabetic patients include: 1) insulin (or insulin secretagogu) doses that are excessive, applied in wrong time or of the wrong type, 2) decreased glucose intake, 3) increased glucose utilization, 4) decreased endogenous glucose synthesis, 5) increased insulin sensitivity and 6) decreased medication clearance because of renal insufficiency. Hypoglycemia is associated with multiple complications, for example cardiovascular diseases (which are the most common cause of mortality in diabetic patients), as well as with cognitive dysfunction and dementia. Finally, it is important to note that hypoglycemia has psychological and social consequences and considerable influence on the quality of life and is a limiting factor in the glycemic control of diabetes because patient’s fear of new hypoglycemia. Therefore, glycemic control should be individualized for every patient. The emphasis must be on an individual approach to every patient, achieving good glycemic control ain order to prevent microvascular complications but with minimal risk of hypoglycemia.