Nasal continuous positive airway pressure (CPAP) is the standard of care for the acute management of preterm infants with respiratory distress, however, the optimal duration of CPAP in stable preterm infants is unknown. In utero, preclinical, and clinical data support the premise that mechanical stretch from CPAP can increase lung growth and development. This paper will review data to support this premise, studies examining weaning infants off CPAP, the current practices in the United States regarding CPAP application and duration, and clinical studies of the association of CPAP duration and subsequent lung growth and development. Pulmonary function testing will be presented as an important outcome throughout these trials.