Hypoglycemia is one of the greatest limitations regarding the treatment of diabetes, as well as one of the most expensive. Its relevance goes beyond the episode itself or the rare sequel. The occurrence of hypoglycemia is frequently followed by treatment adjustments involving the glycemic target, which can result in long term diabetes complications. Its medium and long term consequences are not yet understood in light of recent studies, which have renewed fears regarding an increased cardiovascular risk with its occurrence. Controversy around its definition, as well as serious methodological limitations, led to disparities between the results of the multiple studies of incidence and costs. The low adhesion of a significant number of diabetic patients to glycemic self-monitoring during symptomatic episodes leads to diagnostic uncertainty and, occasionally, to a worsening of the glycemic control. The health-care based studies result in great underestimation of its incidence given the fact that many episodes are mild in nature, and some severe hypoglycemic episodes are treated by the patient's family or friends. Recent studies revealed that a significant number of severe hypoglycemic episodes treated by health-care professionals doesn't involve transportation to an Emergency Department. The same data suggest that the largest portion of the direct and indirect costs of diabetic hypoglycemia is related to the episodes that are treated at the Hospital, particularly if the patient is admitted in the ward. In the past decades a great investment has been made in the development of multiple strategies for the avoidance of hypoglycemia, namely the continuous blood glucose monitoring devices, as well as new drugs. In spite of the efforts, hypoglycemia remains as one of the most important problems in the treatment of diabetes.