Introduction: Spinal anesthesia is commonly used for cesarean section (CS); however, hypotension is a common clinical problem after spinal anesthesia. Prophylaxis ephedrine can safely be administered by bolus intravenous (IV) route which is simple and cheap, because of its longer duration of action than other vasopressors. Methods: A sample size of 88 consecutive parturients scheduled for elective CS under spinal anesthesia was recruited for this study. Based on the responsible anesthetist's management plan, prophylactic group (Group 1) received IV prophylaxis ephedrine (10 mg) with fluid co-loading, while the nonprophylactic group (Group 2) received fluid co-loading only. The drug norepinephrine was used intraoperatively for the treatment of hypotension in both groups. The primary outcome was the incidence of hypotension. Secondary outcomes were blood pressure (BP), first hypotension incidence time, vasopressor for hypotension treatment, and pulse rate (PR). Results: Hypotension occurred in 22 [50.0% (95% confidence interval, CI, 35%–65%)] of patients in nonprophylactic group (Group 2) and 10 [22.7% (95% CI, 10%–36%)] of the patients in prophylactic group (Group 1) [X2 (1, N = 88) = 7.07,P= 0.008]. Mean values of systolic and diastolic BP were significantly different between groups from 5th min until the 20th min [P