To assess the pituitary response to perinatal asphyxia, the prolactin (PRL) and growth hormone (hGH) serum concentrations were measured in 55 asphyctic (15 preterm and 40 full-term) and 35 control (15 preterm and 20 full-term) newborns at 2-4, 24, 48 and 98 h of life. At 2-4 h the median PRL in the preterm asphyctic neonates was 5.2 U/l, whereas in the preterm control newborns it was 3.2. In the full-term newborns with and without hypoxic-ischaemic encephalopathy (HIE) it was 5.8 and 3.4, respectively. In the full-term neonates with HIE the PRL remained significantly higher than in the controls up to the fourth day. At 2-4 h the median hGH in the preterm asphyctic and control newborns was 106.2 and 54.8 mU/l, respectively. In full-term newborns it was 85.0 and 40.8, respectively. The lowest hGH concentrations were found in the severe HIE. The increased PRL and hGH in asphyxia may result from a stress-related hormone release, whereas the very low hGH concentrations in severe HIE may result from a damage at the hypothalamic-hypophyseal axis.