Hypoglycaemia represents a serious medical problem. This phenomenon not only limits intensification of glycaemic control, but it is also related to increased risk of cardiovascular and overall morbidity and mortality. It is frequently an unfavourable effect, frequency of which is growing with glycaemic control intensification as well as with progression of therapeutic steps. The question of iatrogenic hypoglycaemia as an unfavourable effect and potent cardiovascular and also overall risk is a very frequently discussed theme. But these issues need to be observed from different angles of view. Hypoglycaemia, especially severe, undoubtedly presents a serious risk factor, which increases mortality, especially by induction of ischaemia and fatal cardiac arrhythmia. But mortality risk of hypoglycaemia does not depend on the intensity of glycaemic control and reached level of compensation. A very important question in risk evaluation of hypoglycaemia is “a terrain” of the patient, with the need of individualisation at decisions on goals and ways of the glycaemic control. Inclination to hypoglycaemia in individual patients at the same treatment and reached values of the hypoglycaemic control varies and according to several authors it identifies some “more vulnerable, or more ill” patients with comorbidity (hepatic, renal, endocrinological or oncological) and more unstable protective systems, which may itself increase cardiovascular and also overall mortality. So hypoglycaemia represents not only a risk factor but also a marker identifying risk patients. Even if the relation between hypoglycaemia and increased mortality stays the subject for discussions, therapeutic procedures with a low risk of hypoglycaemia and verified cardiovascular and oncologic safety are preferred.