Abstract Respiratory diseases are increasingly recognized as having their origins during perinatal and early postnatal lung development, a time of significant adaptation to large changes in redox conditions as well as to mechanical forces. This Forum of the journal presents a Forum highlighting studies of the interplay between reactive oxygen/nitrogen species and the systems that have evolved to degrade them or exploit them, as well as the cellular repair processes which respond to early life redox stress in the lung. This group of authors suggests new understandings of these events that may point the way to improved therapeutic approaches. Antioxid. Redox Signal. 21, 1819-1822.