Diabetes mellitus is a chronic systemic disease due to a relative or absolute lack of insulin. Hypoglycemia is the clinical occurence most feared when dealing with diabetic patients. The actual level below which blood glucose concentrations are insufficient level at which symptomatic hypoglyeemia occurs is variable. We experienced a case of hypoglycemic shock immediately after induction of general anesthesia on a patient with diabetes mellitus and hypertension. This is the case report and a review of the literature on diabetes mellitus.