Umbilical cord acid-base state and Apgar score were compared in neonates after breech and vertex term birth. The breech group comprised 149 consecutive newborns, 91 born vaginally and 58 by cesarean section. The control group consisted of a random sample of 150 newborns in vertex presentation: 100 born vaginally and 50 by cesarean section. Among vaginally born babies, the 1-min Apgar score was more often depressed in the breech presentation group than in the vertex group; after 5 min the Apgar scores were comparable in both groups. No difference was found in umbilical cord values of pH and base excess between the breech and the vertex groups when comparison was made within each delivery mode. In both greups, umbilical cord values were lower after vaginal than after abdominal delivery. It is concluded that in selected cases, uneventful vaginal breech labor and delivery at term is not associated with an increased risk of asphyxia.