We describe a case of recurrent invasive thymoma associated with myasthenia gravis that responded to combined treatment with prednisolone and tacrolimus. The patient suffered from a myasthenic crisis and received methylprednisolone pulse therapy and partial thymomectomy. Low maintenance doses of prednisolone and tacrolimus shrank the size of the invasive thymoma and maintained the patient without any myasthenic symptoms. We stress the usefulness of combined treatment with tacrolimus and prednisolone for invasive thymoma, especially for unresectable tumors.