This study compared the effects of intravenous infusions of ephedrine and mephentermine for maintenance of maternal arterial pressure and neonatal outcome in pregnant women receiving subarachnoid block for lower segment Caesarean section. Sixty patients who developed hypotension following subarachnoid block for Caesarean section were randomly divided into two groups of 30 each to receive an intravenous infusion of ephedrine or mephentermine. Hypotension was defined as a decrease in systolic blood pressure of > or = 20% from the baseline value or an absolute value of <100 mmHg, whichever was higher. The vasopressor infusion was titrated to maintain systolic blood pressure between 'hypotension' and baseline values. Baseline haemodynamic parameters, haemodynamic changes subsequent to the start of vasopressor infusion, duration of hypotension and amount of vasopressor required were statistically similar for both groups. Neonatal APGAR scores and acid-base profiles were also comparable. To conclude, mephentermine can be used as safely and effectively as ephedrine for the management of hypotension during spinal anaesthesia in patients undergoing elective Caesarean section.