Four unrelated children with the Miller-Dieker syndrome, previously referred to as the lissencephaly syndrome, have been evaluated, bringing to ten the number of patients reported with that disorder. We wish to emphasize that lissencephaly is etiologically non-specific and represents only one feature in this malformation syndrome. Other features, such as the craniofacial, neurologic, and growth abnormalities, are more helpful in diagnosing this autosomal recessive disorder.