The occurrences of thyrotoxicosis in patients with myasthenia gravis have been reported before the knowledge of the pathogenesis of the two disease. Thytotoxicosis is known to occur in 3 to 6 percent of patients with myasthenia gravis and myasthenia gravis occurs in only a fraction of 1 percent of the thyrotoxic populatian. Myasthenia gravis is currently considered as a systemic autoimmune disorder of acetylcholine receptor and often presented with other autoimmune diseases such as SLE, Rheumatoid arthritis. We experienced a 18-year-old woman who presented with graves disease and isolated ocular myasthenia gravis. Chest CT didnot reveal enlarged thymus. The usual treatement of myasthenia gravis associated with thymtoxicosis consists of medical control of the thyrotoxicosis, then thymectomy and later subtotal thyroidectomy. Her ptosis and thyrotoxicosis have improved after the medicatian of anticholinesterase and propylthiourecil. A case of ocular myasthenia gravis with Gravesdisease was experienced, so we reported the case with a brief review of literature.