Objective To examine the effects of the Term Breech Trial on the medical behaviour of Dutch obstetricians and on neonatal outcomes. Design Retrospective observational study. Setting The Netherlands. Population Infants born at term in breech presentation in the Netherlands between 1998 and 2002, with birthweights less than or equal to4000 g (n= 33,024) and >4000 g (n= 2429), respectively. Multiple pregnancies, antenatal death and major congenital malformations were excluded. Methods Data derived from the Dutch Perinatal Database were used to compare modes of delivery and neonatal outcome of infants born in breech position in the 33 months preceding publication of the Term Breech Trial and in the 25 months thereafter. Main outcome measures Incidence of planned and emergency caesarean section, vaginal breech delivery, perinatal death, 5-minute Apgar score and birth trauma. Results Within two months after publication of the Term Breech Trial, the overall caesarean rate increased from 50% to 80% and has remained stable thereafter. In the group of infants less than or equal to4000 g, this was associated with a significant decrease of perinatal mortality from 0.35% to 0.18%, a decrease of the incidence of a 5-minute Apgar score <7 from 2.4% to 1.1% and a decrease of birth trauma from 0.29% to 0.08%. In the (small) group of infants >4000 g, a similar trend was observed. Cnclusions The Term Breech Trial has resulted in an exceptionally rapid change in medical behaviour by Dutch obstetricians. This change was followed by improved neonatal outcome.