The Walker-Warburg syndrome (WWS) is a lethal complex of the central nervous system and the eyes. At present its cause is unknown, but clinical evidence strongly suggests that it is an autosomal-recessively inherited disorder. We report a series of nine children with WWS. The diagnosis was established by the detection of lissencephaly, hydrocephalus, and cerebellar malformation on computed tomography. All children exhibited profound psychomotor retardation and ocular abnormalities (in their anterior or posterior eye chambers). The existence of an occipital encephalocele in eight cases was the main diagnostic clue to WWS. Six patients were investigated for the presence for congenital muscular dystrophy, which was confirmed in only four of them. There were no patients with a cleft lip or palate. We studied the incidence of WWS in Spain and estimated it at 0.21 cases per 10,000 live-born children. In our series, WWS was prevalent in the Spanish gypsy population. Consanguinity was present in five of seven affected families. In a case of pregnancy with twins, one of the siblings was unaffected. Eight patients were treated with ventriculoperitoneal shunts and seven underwent encephalocele repair. Histological study of the excised encephaloceles demonstrated two different patterns. Interestingly, one of the infants showed coronal craniosynostosis. Finally, we include in the appendix, for completeness, a report of the case of the sibling of a WWS patient with acrania-exencephaly.