Dandy-Walker malformation is a rare congenital disease involving the cerebellum and the fourth ventricle. This condition is characterized by agenesia or hypoplasia of the cerebellar vermis, cystic dilatation of the fourth ventricle, and enlargement of the posterior fossa. Approximately 70-90% of patients have hydrocephalus, which often develops postnatally. Dandy-Walker malformation may also be associated to atresia of Magendie’s foramen and, possibly, Luschka’s foramen. Dandy-Walker malformation was described by Dandy and Blackfan in 1914. Then, studies by D’Agostino in 1963 and Hart et al in 1972 defined the characteristic triad of Dandy-Walker malformation as consisting of (1) complete or partial agenesis of the vermis, (2) cystic dilatation of the fourth ventricle and, (3) an enlarged posterior fossa. This triad is typically found in association with supratentorial hydrocephalus, which should be considered a complication rather than part of the malformation complex. The incidence of Dandy-Walker malformation is 1 case/25 000-35 000 live births. Dandy-Walker malformation accounts for approximately 1-4% of hydrocephalus cases. Overall mortality rates of 12-50%, associated congenital anomalies contributed to 83% of postnatal deaths. Dandy-Walker malformation occurs more frequently in females than in males. Dandy-Walker malformation is best diagnosed with the help of ultrasound, magnetic resonance imaging, and computerized axial tomography. The treatment for this condition is based in the management of hydrocephalus.