Periventricular leucomalacia was examined in a total of 28 infants. These foci of infarction were attributed to episodes of failure of perfusion due to hypotension in a border zone between ventriculofugal and ventriculopetal circulations. We describe haemorrhage occurring into these infarctions as a complication occurring in 7 infants. In 2 infants with a bleeding diathesis the haemorrhage was massive and fatal. Descending degeneration of the corticospinal tract was present as a sequel of a large area of periventricular leucomalacia in another case.