The perinatal outcome of 252 consecutive, elective, repeat cesarean section was studied retrospectively. One hundred fifty patients (60%) were scheduled for delivery within approximately seven days of their expected delivery, cesarean (EDC), designated on the basis of rigorous clinical criteria and corroborative sonographic biparietal diameters. One hundred two patients (40%) did not meet these criteria and required analysis of amniotic fluid for L/S ratio and creatinine prior to their operations. Forty-three patients (17%) labored prior to their scheduled procedure or amniocentesis and underwent cesarean section shortly after admission. No cases of the respiratory distress syndrome were noted in the electively delivered patients. The authors conclude that careful clinical assessment of gestational age will prevent the occurrence of iatrogenic hyaline membrane disease in infants born to mothers by elective, repeat cesarean section. When the EDC is in question, however, amniotic fluid phospholipid analysis is clearly advisable.