Occupational asthma is the most common work-related respiratory disorder but frequently goes undetected, leading to poorer clinical outcomes for asthmatic patients. Inhalational exposures to both allergens and irritants in the workplace cause asthma. The likelihood of recovery hinges on early recognition and avoidance of further exposure. This article outlines the clinical approach to the detection, management, and prevention of occupational asthma, emphasizing recent advances and practical advice on how to investigate the causes of reactive airway disease.