Isolated pancreatic metastases from a non-pancreatic primary malignancy are very rare. Studies have shown that resection of metastases is of proven benefit in some types of tumors. We report a case of 76-year-old Taiwanese woman with rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy and abdominoperineal resection 2 years ago presenting with an asymptomatic mass at the pancreatic tail on a routine follow up abdominal computed tomography scan. The patient underwent distal pancreatectomy and splenectomy under the preoperative impression of a primary pancreatic malignancy. Histological examination of the surgical specimen showed metastatic adenocarcinoma. Immunohistochemical studies confirmed the diagnosis of pancreatic metastasis from rectal adenocarcinoma. Postoperative chemotherapy in the form of oral capecitabine was given. The patient is alive and disease free 12 months after the surgery. In a patient presenting with a pancreatic mass with history of a non-pancreatic malignancy, a differential diagnosis of pancreatic metastasis should be considered. Surgical resection of a solitary pancreatic mass is justified not only to get the definitive diagnosis but also to improve the survival.