The iNKT cell represents a unique T-lymphocyte sublineage that has been associated with a broad range of disease processes; including host defense against infectious disease, cancer immunity and allergic autoimmune diseases, such as asthma. Studies in both animal models and human subjects suggest that iNKT cells might significantly affect the course of asthma. This study discusses various aspects of iNKT cell function and how it might lead to an important therapeutic target in asthma (airway hyperreactivity).