In five neonates (4 girls and 1 boy) with aneurysm of the V. magna cerebri, clinical signs of congestive heart failure were encountered. In three of the neonates the symptoms were detected postnatally and in two prenatally. In one of the prenatally detected cases the aneurysm was treated by embolisation during the first week of life. Upon follow-up at six years of age, this patient's situation was stable but hydrocephalus had led to poor visuomotor development, mild motor retardation and mental retardation. In the other infants, medicinal treatment of the congestive heart failure was discontinued in view of ischaemic brain damage, and these patients subsequently died. Congestive heart failure often develops in neonates with an aneurysm of the V. magna cerebri due to low cerebrovascular resistance. A continuous murmur over the skull is pathognomonic for this condition.