A review of the neuropathology of infantile autism shows abnormalities in the limbic forebrain and in cerebellar circuits. The role of the cerebellar lesions in the symptomatology of infantile autism is unknown. The cerebellar findings appear to date from a fetal stage of development with evidence for an ongoing process after birth. The timing of the findings in the limbic system is unknown. A postulated role for these findings in the limbic system in infantile autism is presented.