Hypoglycemic syndrome occurs not only in endocrine diseases but can complicate the course of many somatic diseases and tumors of pancreatic and extra-pancreatic localization. Development of hypoglycemia in liver tumors is associated with a decrease in the volume of functioning liver tissue, increased consumption, and utilization of glucose by the tumor tissue, inhibition of gluconeogenesis and glycogenolysis, and secretion of insulin-like peptides. Hypoglycemia in liver tumors is rarely the first symptom of the disease and usually occurs in patients with large tumor sizes and symptoms of tumor intoxication. Epithelioid hemangiendothelioma of the liver is the primary malignant neoplasm from the group of mesenchymal tumors, it occurs less than in 1% of cases of all malignant neoplasms of the liver. The clinical course of epithelioid hemangiendothelioma of the liver is highly variable. There are slowly and rapidly progressing variants. The diagnosis is based on the results of histological and immunohistochemical examination of the postoperative material. In the literature there is no description of hypoglycemia in epithelioid hemangiendothelioma. We report a patient with severe hypoglycemic syndrome, which was due to an epithelioid hemangioendothelioma of the liver. Pharmacological treatment of hypoglycemia was ineffective. The presence of massive bilobar tumor made it impossible to use a liver resection. Hepatectomy with living related liver transplantation was life-saving procedure and made it possible to eliminate hypoglycemia.