The epithelial cells lining the airways serve as a physical barrier to various external potential injurious agents. Therefore, injury to the epithelial layer results in an immunological reaction to protect the body from infections and other potential toxins. However, these processes can also lead to deleterious effects if the injury is continuous and/or extreme and therefore result in disorders such as asthma and other chronic lung diseases. This chapter will review the potential immunopathogenesis of three childhood lung diseases: asthma, neonatal chronic bronchopulmonary dysplasia (BPD) and cystic fibrosis (CF). Asthma is one of the most common chronic respiratory diseases in both adults and children. Although BPD and CF are not as common both are a source of significant morbidity and mortality and requires not a small amount of resources to manage and treat. Specifically, it will review evidence showing that there is production of various cytokines by epithelial (and other immune cells in the lung) as well as an influx of inflammatory cells upon exposure to various materials such as gas and particles from car emissions, tobacco smoke, pathogens and various allergens such as pollens and animal dander. It will attempt to correlate the pathology with current therapy and suggest future treatment options.