Asthma remains a major problem worldwide, even with new categories of medications that have been brought into the therapeutic armamentarium. One area of disease pathology and physiology that is involved in the pathobiology of asthma is the distal (small) airways. Better understanding of this area in both the pediatric and adult asthmatic populations will lead to improved targeted therapy for all asthmatic patients. This article discusses the importance of the distal airways for both children and adults with asthma.