Antenatal corticosteroids (ACS) successfully reduce the rates of neonatal mortality and morbidity after preterm birth. However, this translational success story is not without controversies. This chapter explores some contemporary controversies with ACS, including the choice of corticosteroid, use in threatened preterm birth less than 24 weeks' gestation, use in late preterm birth, use at term before cesarean delivery, and issues surrounding repeated and rescue dosing of antenatal corticosteroids. The use of ACS in special populations is also discussed. Finally, areas of future research in ACS are presented, focusing on the ability to individualize therapy.