Primary mesenteric liposarcomas are very rare neoplasms. The authors report a case of mesenteric liposarcoma recently observed. The patient presented with a history of dyspeptic syndrome, meteorism and abdominal pain associated with a change in bowel habit and constipation. On physical examination there was a large, well-circumscribed, abdominal mass. Computed tomography revealed an abdominal, dishomogeneous, low-density mass. Surgical excision with a tumour-free margin was achieved. The histologic appearances were those of a well-differentiated liposarcoma (atypical lipomatous tumour). The patient is alive and disease-free 33 months after the surgery. Primary mesenteric liposarcoma is often resectable and requires aggressive surgical management; in consideration of the high risk of tumour recurrence, the treatment of choice is a wide surgical excision.