Neuronal ceroid lipofuscinosis is a common cause of neurodegenerative disease in children. The disease is characterized by visual failure, seizures and dementia. The presence of cortical atrophy by computerized axial tomography and distinctive ultrastructural findings by skin biopsy, together with a suggestive clinical course and neurophysiologic abnormalities, lead to a diagnosis. Presently four subtypes and rare atypical forms are recognized: the infantile, late infantile, juvenile and adult or Kufs variants and atypical early juvenile and protracted juvenile types. The inheritance pattern is autosomal recessive in all subtypes with some of the adult cases representing autosomal dominant inheritance. The biochemical characterization of this disorder is just beginning. There is some evidence to implicate overglycosylation of proteins as playing a role in pathogenesis. Further biochemical description coupled with linkage analysis techniques using DNA probes are needed to develop a better understanding of this group of disorders.