We report the first documented case of a primary leiomyoma of the pancreas. A 72-yr-old female patient was admitted to our hospital for the follow-up of a pancreatic tumor detected 2 yr previously at a different hospital. Diagnostic images revealed the presence of a tumor located in the head of the pancreas. The tumor was characterized by a clear margin, hypervascularity, and was a homogenous mass. Moreover, the tumor had not changed in size or characteristics since a previous computed tomography (CT) scan performed 2 yr previously. The tumor was preoperatively diagnosed as a nonfunctional islet-cell tumor or papillary cystic tumor. During the operation, the tumor was found to be encapsulated and showed no signs of direct invasion to neighboring structure. Tumorous lesions of the liver or swellings of the neighboring lymph nodes suggesting metastasis were not found. Instead of a pancreatoduodenectomy, the tumor was enucleated. Microscopically, immunohistochemical studies of a resected specimen indicated a myogenic origin, and neither mitotic activity nor hemorrhagic and necrotic findings were recognized. No signs of recurrence have been seen since its excision. Accordingly, the tumor was diagnosed as a primary leiomyoma of the pancreas.