Clinical data from 100 neonates with transient tachypnea of the newborn (TTN) and 100 well neonates were compared for the relative incidence of various neonatal and obstetric factors. The incidences of male sex and macrosomia were substantially higher in infants with TTN. Obstetric histories of mothers of neonates with TTN were characterized by longer labor intervals and a higher incidence of failure to progress in labor leading to cesarean delivery. Excessive maternal sedation, perinatal asphyxia, and elective cesarean delivery without preceding labor were not seen more frequently when TTN developed.