In order to assess the rate and amount of fetal uptake of lidocaine after intravenous maternal administration the authors studied 5 pregnant ewes at 118–125 days' gestation. On the basis of a technique previously developed, the animals were prepared by placement of an electromagnetic flow probe on the common umbilical artery to determine umbilical blood flow (u) and by insertion of sampling catheters in the common umbilical vein, fetal aorta, fetal bladder and maternal femoral artery. 3 days later, 7 mg/kg of lidocaine were infused over 50 minutes into the mother and blood samples were obtained as well as urine samples for a period of 5 hours for determination of levels of lidocaine and its metabolites: MEGX and GX. Additional determinations were made of blood gases, u, and protein binding of lidocaine by maternal and fetal blood. Calculations were made of fetal lidocaine uptake rate, total uptake, or accumulation at any time.