OBJECTIVE The scientific literature on occupational asthma is steadily increasing and no longer only describes case reports with prevalence figures and limited physiopathologic and immunologic data. Prospective cohort studies are currently carried out with relevant incidence figures and risk factors. Genetic susceptibility is explored. New diagnostic means are described. Surveillance programs are conducted and preventive measures are proposed. RESULTS A relevant account was published on the respiratory consequences (irritant-induced asthma, a type of occupational asthma) of exposure of firefighters at the World Trade Center site. Glutathione-S-transferase appears to be an interesting susceptibility gene for occupational asthma as a result of isocyanates. Inflammation caused by neutrophils and not only by eosinophils is more often associated with occupational asthma. Examination of induced sputum and assessment of exhaled nitric oxide are becoming useful diagnostic tools. Cleaners are at increased risk of developing occupational asthma, although the causal agents are unknown. Surveillance programs currently combine strategies that aim to reduce exposure and identify cases early. CONCLUSIONS New scientific information provides better, accurate figures on the frequency of occupational asthma and on risk factors, proposes relevant diagnostic tools more directly related to the physiopathology of the disease, and suggests effective surveillance programs in high-risk workplaces.