Methylergonovine is commonly used for the prevention and treatment of postpartum hemorrhage, which promotes contractions of uterine and vascular smooth muscles. However, this drug precipitates serious cardiac complications such as ischemic heart disease, acute myocardial infarction and cardiac arrest in some patients as a consequence of coronary artery spasm. Cardiac complication of methylergonovine is often overlooked by an obstetrician because the frequency of this is very low during postpartum. We report a case of maternal cardiac arrest induced by intravenous methylergonovine which was recovered by prompt cardiac resuscitation and adequate medical treatment during Cesarean section of triplet pregnancy. CASE REPORT Korean J Obstet Gynecol 2012;55(8):578-581 http://dx