A 32-year-old woman experienced subacute onset of weakness in her left leg, urinary retention and difficulty in extending her right middle and third finger. She subsequently suffered episodes of myelopathy, optic neuritis and cerebellar ataxia over a period of several years. Brain MRI showed multiple areas of high signal intensity on T2-weighted images, consistent with multiple sclerosis (MS). However spinal MRI revealed no abnormal findings. In her most recent episode, at age 40 she developed paraparesis. Neurologic examination revealed down beat nystagmus on gazing to the right, horizontal jerk nystagmus gazing to the left, weakness of the right middle and third fingers and paraparesis associated with spasticity of the right leg. Sensory disturbance below C3 and diminished vibration and position sense in both legs were also observed. The patient could not stand or walk, and urinary disturbance was present. Spinal MRI revealed syrinx formation at the level of vertebral bodies C2 to C6. The syrinx within the cervical cord diminished in size after four months, but the patient was unable to walk unaided and had moderate sensory disturbance as before. This finding suggests that the prognosis of MS with syrinx formation following repeated episodes of myelopathy is not always favorable. We believe that functional recovery in MS with syringomyelia is affected by the severity of the demyelination and/or gliosis caused by MS rather than by the presence of the syrinx.