Clinical features of optic neuritis in adults differ from those in children, who often present with atypical clinical manifestations and results of some investigations. This makes the diagnosis of optic neuritis a demanding task. Some investigations, such as the Haitz test, contrast sensitivity test and vision field test, are less reliable in children than in adults. Electro- physiological investigations are the most accurate diagnostic tool for the assessment of optic neuritis in children.This study involved all children referred to the Department of Ophthalmology, University Medical Centre Ljubljana, because of suspected optic neuritis during the past two years. The children were invariably evaluated by the vision field testing, Haitz test, contrast sensitivity test and electrophysiological investigations, including flash and pattern electroretinography (ERG) and visual evoked potentials (VEP). The results were compared with those obtained in a group of healthy volunteers of the same mean age.The diagnosis of optic neuritis should always be considered in a child presenting with a considerably reduced visual acuity refractory to correction in the presence of a normal ophthalmologic status, associated with disc hyperaemia, blurred optic disc margins, relative afferent papillary defect, or subjective problems, such as blurred vision, double vision and painful eye movements.The diagnosis of optic neuritis cannot be made on the grounds of clinical findings alone, especially in children with a relatively well preserved visal acuity. In our study, 3 children with suspected optic neuritis had delayed and decreased VEP but normal flash and pattern ERG. Since the results were not very convincing, the children will be followed up. Careful evaluation of children with suspected optic neuritis is of utmost importance as clinical and functional investigations are not accurate enough for a definitive assessment and prognosis of the visual path defect. Atypical optic neuritis at this age may, though rarely, herald the onset of demyelinating disease. Electrophysiological testing has proved a reliable diagnostic instrument for identifying the level of the visual pathway defect in children.