A 4-year-10-month-old boy with late infantile type neuronal ceroid lipofuscinosis was reported. He presented with progressive dementia, loss of visual acuity, gradual regression of speech and motor functions, and myoclonic jerks. A hyperactive deep tendon reflex was noted, but there was neither muscle weakness nor hepatomegaly. Serum lactate, pyruvate and ammonia levels were within normal limits. The funduscopic examination showed diffuse mottling of the retinal pigmented epithelium. The electroencephalogram showed irregular bilateral spike-and-waves or polyspike-and-waves and isolated focal spikes from the bilateral parieto-occipital regions. The wave forms of visual evoked potentials were flat. The electroretinogram was unrecordable. The somatosensory evoked potentials showed prolonged central conduction times from bilateral median nerves. The brainstem auditory evoked potentials were within normal limits. Diffuse cerebral and cerebellar atrophy were noted on magnetic resonance imaging. The diagnosis was confirmed by the electron-dense cytoplasmic inclusion bodies within the conjunctival squamous epithelial cells. No specific treatment was available. Regular anticonvulsants were not given during follow-up because seizures attacked him only on occasion. His visual acuity was progressively impaired. In addition to nearly total absence of speech, an inability to communicate and walk independently was also noted. The clinical features according to the subtypes, radiology, pathology, managements and prenatal diagnosis for this case are discussed.