During the period from September, 1974, to January, 1975, we performed 276 deliveries, of which 54% were internally monitored with a spiral type of fetal electrode. Eight of the infants monitored (incidence, 5.4%) developed scalp abscesses. We had had no previous complications associated with the electrodes. An intensive investigation was conducted to detect the causative factor(s) of the fetal scalp infections. Case histories of the mothers and infants were scrutinized, instruments were examined, the environment and techniques were analyzed. A survey of maternal and infant complications during the period from September, 1973, to August, 1974, served as control. The findings indicated that a different type of coil electrode had been substituted for the brand we had used previously. The new coil electrode had a barb at the tip, presumably to prevent its falling out of the scalp. We discontinued the use of the coil which had become suspect and returned to the type we had used previously. We have not had another incidence of fetal scalp infection associated with intrapartum monitoring.