Three cases of bilateral optic neuritis, one of which also had transverse myelitis, are described in young adults following chickenpox. Severe bilateral loss of vision developed in all cases and was followed by good visual recovery in the two with isolated optic neuritis, but poor recovery in the patient with concomitant transverse myelitis. The interval between the initial rash and subsequent optic neuritis suggests an immunological pathogenesis for this complication.