The objective of this study was to determine the impact of undetected breech presentation on an external cephalic version program. We performed a retrospective analysis of all external cephalic versions attempted over a 1-year interval. We then analyzed all cesarean operations performed for the indication of breech presentation over the same interval. Cases involving twin gestations and premature births were excluded. We found that 21% of term breech presentations were not detected before the onset of labor and an additional 15% were not detected until after 38 weeks' gestation. Increased third-trimester screening for breech presentation could potentially decrease the need for cesarean delivery.