The incidence of periventricular leukomalacia (PVL) in risk neonates was evaluated in a prospective ultrasound study at the Pediatric Hospital of the Medical Faculty, University of Rostock. The study was carried out in 300 registered risk neonates. These risk neonates were divided into 3 groups: < or = 31 gestational week (n = 70), 32-36 gestational week (n = 154), > or = 37 gestational week (n = 76). A prenatal PVL was diagnosed in 41 neonates, a postnatal PVL was found in 56 neonates after the 5th day of life. In 77% of all risk neonates with PVL, the diagnosis was made on the first day of life. After the first day of life, PVL was presented mainly in highly immature neonates. A correlation of PVL to gestational age could only be found in neonates with postnatal PVL. Subarachnoid space enlargement was found to be significantly more frequent in risk neonates with prenatal PVL than in risk infants with postnatal PVL. Residual ultrasound findings of PVL were significantly more frequent in male than in female risk neonates.