The so-called dead-in-bed syndrome refers to sudden death in young diabetic patients without any history of long-term complications. Autopsy is typically negative. The present report summarizes frequency data on this condition from studies in the U.K. and the Scandinavian countries. It appears that such deaths occur in 6% of all deaths in diabetic patients below age 40 years. The frequency may also be expressed as 2-6 events per 10,000 [corrected] patient-years. The causes are by definition unknown, but a plausible theory is a death in hypoglycemia, since a history of nocturnal hypoglycemia is noted in most cases. While waiting for the clarification of the underlying pathophysiology, one should attempt to identify patients who are at particular risk of hypoglycemia and advocate caution in efforts to normalize blood glucose and HbAlc in these cases.