Somatostatinoma is a rare neoplasm usually arising from the pancreas and duodenum which typically presents with indolent, nonspecific symptoms in the absence of systemic neuroendocrine manifestations that characterize somatostatinoma syndrome. It accounts for less than 1% of all gastrointestinal endocrine tumors with an annual incidence of 1 per 40 million. It is often associated with regional and/or portal metastasis at the time of diagnosis, and complete tumor resection is possible only in 60% to 70% of cases. We experienced a case of pancreatic somatostatinoma recently. A 51-year-old woman presented with right upper quadrant abdominal pain and loose stool for one month. A hypermetabolic lesion in the pancreatic head was detected on positron emission tomography-CT (PET-CT) scan. The tumor was resected by pylorus preserving pancreaticoduodenectomy. Immunohistochemical staining of the tumor tissue exhibited diffuse positivity for somatostatin, but was negative for insulin and glucagon. Herein, we report a case of pancreatic somatostatinoma diagnosed postoperatively.