The prophylactic use of small doses of ephedrine may counter the hypotension response to propofol anesthesia with minimal hemodynamic changes. One hundred-fifty patients scheduled for valve surgery were randomly assigned into five groups (n = 30 for each) to receive saline, 0.07, 0.1, or 0.15 mg/kg of ephedrine, or phenylephrine 1.5 μg/kg before induction of propofol-fentanyl anesthesia. After induction, patient receiving ephedrine had higher mean arterial pressure, systemic vascular resistance (SVRI), cardiac (CI), stroke volume (SVI), and left ventricular stroke work (LVSWI) indices. Patients received 0.15 mg/kg of ephedrine showed additional increased heart rate and frequent ischemic episodes (P < 0.001). However, those who received phenylephrine showed greater rise in SVRI, reduced CI, SVI, and LVSWI and more frequent ischemic episodes. We conclude that the prophylactic use of small doses of ephedrine (0.07-0.1 mg/kg) is safe and effective in the counteracting propofol-induced hypotension during anesthesia for valve surgery.