Apgar scores and umbilical cord arterial pH measurements of 449 singleton breech deliveries are compared retrospectively to those of 1425 singleton vertex neonates. In the vaginal deliveries the Apgar scores and umbilical arterial pH were higher for the vertex neonates. There were no differences in either Apgar scores or umbilical arterial pH between the breech and vertex neonates delivered by cesarean section. Whereas Apgar scores in the less than 1000 g and greater than or equal to 2500 g weight groups were lower in the breech neonates delivered vaginally compared to cesarean section, umbilical arterial pH measurements were similar. The data suggest that liberal use of cesarean section may improve the Apgar scores but will probably not appreciably improve the acid-base status of the breech neonate.