Myasthenia gravis is an autoimmune disease characterized by motor plaque dysfunction due to antibodies against post-synaptic membrane proteins. Myasthenic symptoms classically wax and wane and are more intense at the end of the day, although they may be constant in severe pictures. Almost every patient have eyelid ptosis and double vision, and the majority of them also have proximal muscle weakness. Reversible cholinesterase inhibitors are the first-line treatment, but patients who do not achieve symptom control should receive immunosuppressive therapy, whose options include azathioprine, cyclosporine, mycophenolate, intravenous immunoglobulin and thymectomy, with different profiles of efficacy, safety and tolerability. For more than a decade, rituximab, an immunobiological agent directed against B lymphocytes, has been shown to be effective in case reports and series of cases of refractory myasthenic patients, showing few side effects. We report the case of a patient with an excellent response to 3 infusions of rituximab with intervals between 9 and 12 months between each.