The respiratory system undergoes many changes with maturation, resulting in increased capacity and efficiency. In an effort to determine the effects of maturation on airway control, laryngeal airway resistance was studied from infancy to adulthood in dogs. Reflex regulation of laryngeal airway resistance in response to chemoreceptor stimulation was found in puppies 1 day of age and older. Chemoreceptor-mediated laryngeal reflexes were qualitatively similar in all age groups. However, a significant quantitative difference was found. With maturation, an increase in the sensitivity of both central and peripheral chemoreceptors regulating laryngeal resistance is realized.