We present the case of a 72‒year‒old male patient with anorexia who was diagnosed with advanced gastric cancer with multiple liver metastasis. He had marked hypoglycemia and lightheadedness from the time of admission. The serum insulin level was very low and other endocrinology test results were normal. He was finally diagnosed with non‒islet cell tumor hypoglycemia(NICTH)based on IHC findings that tumor cells expressed insulin‒like growth factor (IGF)Ⅱ. After the patient received intravenous glucocorticoid therapy along with S‒1 plus CDDP combination chemotherapy, the hypoglycemia was quickly resolved. However, he developed septic shock in reaction to the chemotherapy and died on the 35th day of hospitalization. The autopsy showed the presence of IGF‒Ⅱ in the liver metastasis, as well as in the primary tumor.