Childhood-onset schizophrenia is a rare, clinically severe form of schizophrenia, which is associated with disrupted cognitive, linguistic, and social development well before the appearance of frank psychotic symptoms. This disruption of multiple developmental domains signals the important opportunity these patients present for examining neurodevelopmental and other etiologic hypotheses of schizophrenia. The present research update reviews studies of the phenomenology and neurobiology of childhood-onset schizophrenia conducted since 1994. Findings from these studies indicate that children can be diagnosed with schizophrenia using unmodified DSM-III, -IIIR, and -IV criteria, and that the atypical neuroleptic clozapine is an effective medication for this treatment refractory group. Neuropsychologic and neurobiologic studies generally support continuity with adult-onset schizophrenia, with evidence of more severe premorbid impairment. Longitudinal studies show preliminary evidence of progressive ventricular enlargment and more prolonged deterioration in intellectual function than is seen in the adult-onset disorder. If replicated, these observations, together with the insidious onset of this disorder, would suggest that the pathologic underpinning of childhood-onset schizophrenia is not a single static lesion or event but may be a continuous or multi-event process.