Our aim was to compare the respective values of base deficit and lactate in birth asphyxia. Methods: Base deficit and lactate levels were measured from radial artery blood samples taken at 30min of life in 115 term newborns suspected as having been asphyxiated during labour. Both base deficit and lactate levels were compared between patients who further developed moderate or severe encephalopathy and those who experienced no or only mild encephalopathy. Receiver operating characteristics curves and clinical values of both indicators were computed. Results: The correlation between base deficit and lactate was significant (r2= 0.51, p < 0.0001). Both indicators were significantly associated with neonatal outcome. Lactacidaemia lower than 5 mmol/l and/or base deficit level lower than 10 mEq/l were not followed by neurological complications. Plasma lactate concentration greater than 9 mmol/l was associated with moderate or severe encephalopathy with a sensitivity of 84% and a specificity of 67%. Base deficit and lactate had similar clinical values. Conclusions: Base deficit and lactate measurements in arterial blood at 30 min of life are equally valuable in assessing the severity of birth asphyxia.