We report the first case of adenocarcinoma of the stomach associated with severe hypoglycemia. Accompanying the profound hypoglycemia, as low as 5 mg per cent by the orthotoluidine method, were multiple episodes of ventricular tachycardia which were abolished by glucose infusion. Following surgical excision of a hemorrhagic portion of the tumor, normoglycemia levels were achieved and ventricular irritability was no longer present. The possible mechanisms of hypoglycemia in extrapancreatic tumors are discussed as well as a mechanism for hypoglycemic-induced ventricular tachycardia. It is postulated that hemorrhage of a necrotic tumor may release large amounts of an insulin-like substance and cause hypoglycemic coma.