A 45-year-old female who presented with loss of consciousness and a cold sweat was found to have a pancreatic tumor and multiple liver metastases. Laboratory studies showed marked hypoglycemia and inappropriately elevated serum insulin, C-peptide, and serum tumor markers. Fine needle aspiration revealed Grade 3 small-cell type primary pancreatic neuroendocrine carcinoma. Consequently, the diagnosis of malignant insulinoma was made. Transarterial embolization (TAE) for hepatic metastases resulted in the reduction of tumor volume and prompt resolution of hypoglycemic attacks, whereas diazoxide and systemic chemotherapy had been ineffective for controlling blood glucose levels, and octreotide was unavailable due to the allergic effect. This case report highlights the potential usefulness of TAE for malignant insulinomas in the management of hypoglycemia.