Purpose In order to prevent postpartum hemorrhage in caesarean section under spinal anesthesia, patients routinely receive oxytocin. In this study we compared the efficacy of Methylergonovine and Oxytocin on hemodynamic stability and bleeding amount in caesarean section. Materials and methods In this randomised controlled trial study, 80 patients candidate for elective caesarean section under spinal anesthesia divided to two groups: 40 patients in control group received oxytocin and 40 ones in case group received methylergonovine. Results There was no differences between groups in Mean age, baseline hemodynamic values, after spinal anesthesia and recovery (except diastolic blood pressure min 20), time of uterine atony, dizziness; nausea and vomiting. After drug administration (oxytocin and methylergonovine), systolic blood pressure in minutes 1, 10, 15 and diastolic blood pressure in minutes 1, 3, 20 increased in case group statistically more than control group. In control group, heart rate in minutes 1, 5 increased significantly more than the other group. Mean arterial blood pressure in minutes 1, 3, 5, 10, 15 reduced significantly more than in control group. Need to vasoconstrictor drug statistically was less in case group (p \ 0.0001). Conclusion Methylergonovine induced significantly more hemodynamic stability. Adverse effects were similar between two groups. We recommend the use of methylergonovine in patients with caesarean section under spinal anesthesia because of its hemodynamic stability and low need to vasoconstrictor drugs.