Acute myelitis is an aetiologically heterogeneous inflammatory disorder of the spinal cord. We report on a 71-year-old woman with a recurrent cervical and thoracic myelitis who presented with a new relapse of the disease. Neuromyelitis optica was ruled out such as other possible causes of acute and/or recurrent myelopathy. Serum immunoglobulin levels and specific antibody responses were consistent with the diagnosis of common variable immunodeficiency (CVID). She was treated with high-dose methylprednisolone and intravenous immunoglobulin. As a remission-maintaining drug, we decided to treat her with subcutaneous immunoglobulin (CSL Behring) at 0.2 g/kg/week at doses higher than usually employed in replacement therapy in CVID. At 3-year follow-up, the response to treatment was good. No relapses occurred. Our case suggests the effectiveness and safety of subcutaneous immunoglobulin in maintaining remission and in sparing prednisone in a woman with recurrent myelitis associated with CVID.