A 35-year-old young man displayed Leber's optic neuropathy (LHON) due to T14484C and multiple sclerosis (MS) phenotype that was dominated by symptoms and signs of spinal cord impairment. Magnetic resonance imaging (MRI) revealed demyelinating lesions extending from D6 to D11 in the spinal cord with gadolinium enhancement, while only three linear demyelinating lesions were seen on brain MRI. In the literature, a major involvement of the spinal cord was already reported in three of four male patients with the 14484 LHON mutation who developed MS, but the reasons of this peculiar association remain unknown, and further research in this area is needed.