A retrospective and prospective analysis of children with a diagnosis of complete absence of the corpus callosum (ACC) at the Children's Memorial Hospital in Chicago over a 5-year period was performed. The diagnosis was based on the computed tomography (CT) and/or magnetic resonance (MR) images. From this material, 105 children with a diagnosis of ACC were analyzed on the basis of clinical symptomatology and radiological studies (CT, MR and ultrasound). Eighty-three percent of our children were symptomatic. The most common symptoms and signs were macrocephaly with hydrocephalus and seizures. MR was the best radiological imaging modality for evaluating children with ACC and associated brain anomalies. The most common associated brain anomalies with ACC in decreasing frequency in our children were: interhemispheric cyst with hydrocephalus, Dandy-Walker malformation, migrational disorders, absence of the inferior vermis, cephaloceles and lipoma of the interhemispheric fissure.