Biotinidase deficiency is an autosomal recessively inherited metabolic disorder characterized by neurological and cutaneous manifestations and metabolic abnormalities. We studied 78 symptomatic children and found that 51% had ophthalmologic abnormalities. These include infections (30%), optic neuropathies and visual disturbances (13%), motility disturbances (13%), retinal pigment changes (4%) and pupillary findings (1%). The most commonly reported findings are optic atrophy and keratoconjunctivities. Although the disorder can be effectively treated with biotin therapy, untreated children are at risk of developing permanent neuro-ophthalmic damage.