The clinical and radiographic findings in four cases of cerebral hemiatrophy are presented. CT findings reflect the underlying gross pathologic changes and are in agreement with those seen on plain skull radiography and pneumoencephalography. The most impressive finding was unilateral loss of cerebral volume with ipsilateral displacement of the midline structures. The differential diagnosis primarily includes Sturge-Weber syndrome and linear sebaceous nevus syndrome. The recognition of compensatory calvarial changes should indicate that the cerebral abnormalities are the result of an atrophic or hypoplastic process that began in early life.