Currently, preoperative hemodynamic measurements are of limited value in the selection of patients for portosystemic shunt surgery. Wedged hepatic vein pressure measurement accurately assesses portal pressure in alcoholic liver disease and can be helpful in the diagnosis and follow-up of portal hypertension but not in the selection of patients for surgery. Though theoretically useful, hepatic blood flow measurement has not been shown to correlate with results of surgery. New methods have been developed for measurement of portal blood flow preoperatively, which use the umbilical vein approach. Assessment of hepatic arterial response to portal flow diversion is also feasible with the patient under local anesthesia. Hopefully, one of these measurements will prove useful in selecting those patients who can undergo portosystemic shunt without a high risk of postoperative encephalopathy or hepatic failure.