Dandy-Walker syndrome is a particular form of hydrocephalus whose main feature is the transformation of the IV ventricle into a large cyst, which occupies almost the whole of the posterior fossa; the latter, owing to the lifting of the tentorium cerebelli and bulging of the occipital bone, is enlarged. The pathogenesis is incertain; it is generally agreed that it is originated from a developmental disorder brought about by the non-opening of the foramina of Luschka and Magendie. In the literature were found 60 cases reported. Four additional cases are reported, two of which underwent the ventriculo-jugular shunt by Spitz-Holter's technique. The main clinical signs, laboratory data and therapy are discussed. The abnormally high position of the transverse sinuses, as seen in the X-ray of the skull or in the sinugram, is considered a pathognomonical sign. The trans-illumination of the skull may also show a characteristic aspect. When the results of these exames are typical, it is possible to avoid more traumatizing ones such as ventriculographies. The therapy more commonly used is the opening of the wall of the cyst. There is no reference in the literature to Spitz's operation, which is, in our opinion, the best treatment.