Joubert's syndrome is an autosomal-recessive condition characterized by dysgenesis of the cerebellar vermis, hypotonia, developmental delay, a respiratory pattern of alternating tachypnea and apnea, and abnormal eye movements. Radiologic findings include a midline cerebellar cleft in place of the vermis and a characteristic shape of the fourth ventricle. Prenatal hydrocephalus has been proposed as a possible etiology for the cerebellar abnormalities but has not previously been described in association with this syndrome. The authors report a patient with clinical and radiographic features consistent with Joubert's syndrome who presented with congenital hydrocephalus.