Optic neuritis is a common clinical condition that causes loss of vision. It can be clinically isolated or can occur as one of the manifestations of multiple sclerosis. Multiple sclerosis is a severe disabling demyelinating disease of the central nervous system, which is rare among children. The treatment of optic neuritis has been investigated in several trials, the results of which have shown that corticosteroids speed up the recovery of vision without affecting the final visual outcome. Treatment of neurologic disorders with intravenous immunoglobulin is an increasing feature of our practice for an expanding range of indications, including multiple sclerosis. Owing to its anti-inflammatory properties, intravenous immunoglobulin can be beneficial in the treatment of acute relapses and in the prevention of new relapses of multiple sclerosis. To our knowledge, there is only one experience of treatment of optic neuritis with intravenous immunoglobulin in multiple sclerosis, even if therapeutic trials are used in the therapy of multiple sclerosis. We report on a girl with optic neuritis and multiple sclerosis in whom treatment with intravenous immunoglobulin at first alone and subsequently associated with interferon achieved great improvement in visual acuity.