Glucagonoma, a rare tumor derived from the α-cells of the pancreas, has an estimated incidence of approximately one in 20 million people per year. This glucagogenesis results in clinical manifestations including necrolytic migratory erythema (NME), cheilitis, diabetes mellitus, anemia, weight loss, among others. Of these, NME is a well-known paraneoplastic symptom observed in patients with glucagonoma. However, NME is often missed at initial investigation, and the correct diagnosis of glucagonoma tends to be delayed.We report a 46-year-old Japanese woman with glucagonoma who presented with mucocutaneous manifestations 1 year before the diagnosis of the pancreatic neoplasm with multiple liver metastases. Contrast-enhanced dynamic CT of the abdomen revealed multiple tumors in the pancreatic tail and liver, which were enhanced during the early arterial phase and washed out in the delayed phase. Liver biopsy showed well-differentiated neuroendocrine tumor. These histopathologic features in skin biopsy were suggestive of NME. Serum glucagon concentration was 8,400 pg/ml (normal range 70-160 pg/ml). Based on these findings, the diagnosis of glucagonoma with NME was confirmed. Because she had unresectable metastatic disease, she was treated with octreotide, a somatostatin analog. NME was dramatically improved within 2 weeks after initiation of octreotide. The rarity of glucagonoma has hampered a closer understanding of its pathophysiological mechanisms, which together with its non-specific clinical manifestations means that diagnosis is often relatively late in the course of the disease. Though several novel agents such as octreotide, sunitinib and everolimus provide clinical benefits for patients with advanced glucagonoma, complete resection still represents the only potentially curative treatment. Earlier recognition of NME, the characteristic skin lesion of glucagonoma syndrome, will facilitate the correct diagnosis of this condition.