Dandy-Walker syndrome is characterized by a triad of complete or partial agenesis of the cerebellar vermis, cystic dilatation of the forth ventricle and enlarged posterior fossa with upward displacement of the transvers sinus, tentorium and torcular. The most striking abnormality is the presence of a huge dilated forth ventricle which acts as a cyst and is roofed by a neuroglial-vascular membrane lined with epandyma.This cyst herniates caudally and separates the cerebellar anteriorly and choroid plexus are rudimentary the formation of the fourth ventricle are often occluded by membranes or are atretic. A varient form, in which is cystic dilatation of the fourth ventricle and hypoplasia of the cerebellar vermis without enlargement of the posterior fossa is more common than the classic Dandy-Walker malformation and account for onethird of posterior fossa malformations. Hydrocephalus is precent in 90% of patients. Some of the patients have other malformations associated with this syndrome include, Occipital Encephalocel, facial angioma,midline cleft palate, cardiovascular malformations and polycystic kidney. Hydrocephalus is not present at birth. It often appears by 3 months of age. In some instance, hydrocephalus fails to develop and this condition remains Asymptomatic throughout life. Prenatal diagnosis with ultrasonography and Postnatal diagnosis with CT scan and MRI in progressive hydrocephalus Treatment is surgical. Befor birth in 10 embrio, dandy walker syndrome was diagnosed with ultrasound, that after delivery, diagnosed and confirmed in eight cases. The case was male and 2nd product of non consanguinous marriage.This study is a case report of Dandy-Walker syndrome in a newborn.