A case of sinusoidal fetal heart rate (FHR) pattern in association with maternal intrapartum administration of meperidine is presented. The sinusoidal pattern was reversed after maternal intrapartum administration of naloxone. The significance of this problem and the management of patients with sinusoidal FHR are discussed. The conclusion is reached that iatrogenic causes may at times precipitate a sinusoidal FHR pattern and conservative management may be appropriate.