Myxofibrosarcoma is a soft tissue sarcoma that occurs in elderly patients. Primary myxofibrosarcoma rarely arises in the mesentery; this is the fourth known case of myxofibrosarcoma presenting as a mesenteric tumor. A 62-year-old male with a mesenteric myxofibrosarcoma presented with an abdominal mass; his symptoms were frequent urination and a sense of abdominal pressure. He was admitted for further examination. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a mesenteric lesion. The preoperative diagnosis was a suspected malignant myxoid tumor. We performed a curative resection with wide margins. The histopathological and immunohistochemical findings confirmed that the tumor was mesenteric myxofibrosarcoma. The postoperative course was uneventful, and there have been no signs of relapse for three years to date after surgery. It is difficult to make a definitive diagnosis of mesenteric myxofibrosarcoma using only CT or MRI. However, when the preoperative findings suggest a malignant mesenteric tumor, then the best practice is resection with sufficient margins.