Hypoglycaemia is a common occurrence in patients treated for type 1 and 2 diabetes and a major barrier to the attainment of good glycemic control. Hypoglycaemia has immediate clinical and psychosocial consequences and significantly increases health care costs. Hypoglycaemia has been associated with serious vascular and non-vascular events. Better detection and understanding of the management of hypoglycaemia is urgently needed. Prevention is critical and must consider patient factors as well as therapies.