Background: Systemic lupus erythematosus (SLE) is one of the autoimmune diseases, which is rarely reported with Myasthenia Gravis (MG). In the literature, the clinical features of MG in these patients were not mentioned in detail. Here, we want to present our five patients with MG and SLE. Methods: Between 2000 and 2010, 132 MG patients were evaluated and have been followed up in our institution. Five patients had MG with SLE and eleven patients had antinuclear antibody (ANA) positivity without SLE symptoms. The clinical, laboratory findings and treatment responses were reviewed. Results: All patients had generalized MG and four of five patients experienced at least one myasthenic crisis. The response to corticosteroid was poor; consequently, they needed immunosuppressive treatments, IVIg or plasmapheresis. Although in the literature thymectomy was accused of the precipitation of SLE, in our series SLE symptoms preceded thymectomy. Conclusion: We would like to point out that MG and SLE being two autoimmune diseases may coexist. This coexistence might cause a more severe myasthenic course compared to MG alone; therefore, these patients need a close and frequent follow-up.