Isocyanate allergy and asthma is an important respiratory disease in most industrialized countries. Little information about its importance is available for the Netherlands. A baseline survey, part of a larger longitudinal epidemiological survey, shows that exposure to mainly HDI monomers and oligomers is present. The respiratory symptoms prevalence, especially of work related symptoms, is high and sensitization to isocyanates was observed in some cases. A more detailed evaluation is required to get insight in the magnitude of isocyanate exposure related respiratory disease.