Airway responsiveness may be defined as the case with which airways narrow upon exposure to physical and chemical stimuli and drugs. Bronchial hyperresponsiveness reflects an excessive bronchoconstricting response to these stimuli. Although in part it may be genetically mediated, a number of environmental factors (allergens, viruses and contaminants) are also involved in increasing bronchial responsiveness through airway inflammation. We review the concept, etiology, pathogeny, clinical expression, diagnosis, preventative measures and treatment of bronchial hyperresponsiveness in pediatrics.