This report addresses behavioral abnormalities in children with cerebellar anomalies demonstrated on MRI scans. Published data are presented showing an interaction between cerebellar pathology and early childhood autism. The cerebellum is involved not only in movement coordination, but also in social adaptation and verbal communication. The genes expressed in the cerebellum during childhood are identical to those expressed in the hippocampus. We have observed 20 children with MRI-identified agenesis of the cerebellar vermis and behavioral abnormalities; children were aged 3-15 (mean 7.05) years and there were 12 males and eight females. A variety of autistic characteristics were identified in these children.