A 41-year-old woman presented to our department with a 2-year history of unilateral painful swelling of the right eye. Clinical and laboratory evaluation ruled out endocrine, infectious and neoplastic disorders, and suggested the diagnosis of systemic lupus erythematosus. Echographic examination of the orbit and CT-scan revealed enlargement of the lateral and inferior rectus muscles at the right side, and enlarged medical rectus muscle at the left side. Despite the involvement of the extraocular muscles the patient did not have any ocular motility defects nor diplopia. The condition responded rapidly to systemic corticosteroids associated with immunosuppressive agents.