Rare congenital malformation in the form of an aneurysm of the vein of Galen was diagnosed in an 18-day-old newborn by brain ultrasound, MRI and digital substraction angiography (DSA). Meningeal syndrome, intracranial hypertension and hydrocephalus occured as the main clinical signs. After DSA the aneurysm thrombosed spontaneously. Neurosurgical treatment was not needed, although there had been preliminary enlargement of the hydrocephalus. At the age of six months the hydrocephalus was compensated. At the age of one year the development of the child corresponded to age.