carbetocin, a potentially cardio toxic drug is used by intravenous bolus for uterine bleeding prevention during cesarean section. The aim was to assess the cardiac effects of carbetocin in patients undergoing cesarean sections. a pretest-postest design study was carried out on 74 women (23 ± 5.3 years, ASA I-II classification, no history of pregnant induced-hypertension) who underwent elective or emergency cesarean section. At surgical room entry (baseline), and after administration of carbetocin (infunded 100 μg along 30 minutes) during the anesthesic-surgical follow up, vital signs and EKG were registered; and CK, CK MB, and troponin I blood levels were measured. Wilcoxon's rank test was used. significant changes were found on CK (30 vs. 58), CK MB (4.0 vs. 5.9), troponin I (0.01 vs. 0.03), blood sistolic pressure (110 vs. 100), blood diastolic pressure (70 vs. 60) and heart rate (76 vs. 90); all of them: p < 0.001. However, no patient showed heart ischemia signs during EKG monitoring. an increase on biochemical indicators of myocardiac damage blood levels was observed after the administration of a carbetocin bolus in patients underwent cesarean section.