Occupational asthma (OA) is the most common of all occupational lung diseases in industrialized countries and its prevalence has been rising steadily. It is estimated that occupational factors account for one out of six cases of adult asthmatic patients causing significant morbidity, disability and costs. Due to its high prevalence and substantial health and socio-economic impacts OA represents a significant public health concern. OA can be divided into allergic and non allergic asthma. Allergic OA is further divided into IgE mediated and non IgE mediated. Baker's asthma (BA), is the leading cause of IgE mediated OA caused by high molecular weight antgens in industrialized countries. Innovations in the baking industry during the last few decades have led to the introduction of new allergens inducing OA. OA is potentially preventable, through early diagnosis and exposure cessation interventions. Thus, clinicians should consider the occupational history in every adult patient presenting with newly diagnosed asthma.