Our purpose was to determine correlation between fetal scalp lactate and fetal scalp pH during labor and to compare the predictive value of intrapartum scalp lactate with that of scalp pH for an abnormal neonatal outcome in case of an abnormal fetal heart rate (FHR). Prospective trial including 213 consecutive patients with abnormal FHR patterns for which a simultaneous measurement of scalp lactate and pH is made. A measurement of lactate, pH and base excess were also realized on umbilical artery. This technique needs less fetal scalp´s incisions and has no failure whereas there are 4 % of failures for scalp pH´s measurement. In our trial, the 90th percentile was at 5.0 mmol/L for scalp lactate and at 6.4 mmol/L for the umbilical artery lactate. There was a significant correlation between scalp lactate and scalp pH (r = −0.28; P < 0.01) and between scalp lactate and umbilical artery lactate (r = 0.31; P < 0.01). There was also a significative correlation between umbilical artery lactate and umbilical pH (r = −0.64; P < 0.001). For the comparison with scalp pH, only the 33 scalp lactate´s measurements obtained during the 30-minutes before the delivery were taken into account. At a 5.0 mmol/L threshold for scalp lactate and 7.20 for scalp pH, the predictive value of lactate was similar to that of pH for an arterial umbilical pH 7.15 (positive predictive value 67% vs 33%, negative predictive value 79% vs 67%, sensitivity 55% vs 9%, specificity 86% vs 67%, respectively). The scalp lactate is significantly correlated with scalp and umbilical pH. The predictive value of scalp lactate can be favorably compared with that of scalp pH.