Objective-To highlight emerging evidence for clinical and biological links between autism/ Pervasive Developmental Disorder (PDD) and schizophrenia, with particular attention to childhood onset schizophrenia (COS).Method-Clinical, demographic and brain developmental data from the NIMH (and other) COS studies, and selected family, imaging and genetic data from studies of autism, PDD and schizophrenia were reviewed.Results-In the two large studies that have examined this systematically, COS is preceded by and comorbid with Pervasive Developmental Disorder in 30%-50% of cases. Epidemiologic and family studies find association between the disorders. Both disorders have evidence of accelerated trajectories of anatomic brain development at ages near disorder onset. A growing number of risk genes and/or rare small chromosomal variants (micro-deletions or duplications) are shared by schizophrenia and autism.Conclusion-Biological risk does not closely follow DSM phenotypes and core neurobiological processes are likely common for subsets of these two heterogeneous clinical groups. Long-term prospective follow up of autistic populations, and greater diagnostic distinction between schizophrenia spectrum and autism spectrum disorders in adult relatives are needed.