The purpose of this study was to describe the prevalence of respiratory symptoms and skin prick test findings in a group of 383 employees in a plant bakery population who had the greatest regular exposure to ingredient dusts. The prevalence of positive skin prick tests to fungal amylase was 16%, in contrast to 6% to wheat flour, suggesting that the principal sensitiser is fungal amylase and not flour. Furthermore, the findings suggest that symptomatic allergy to bread-baking ingredients is uncommon (3.1%). In comparison, occasional short-lived symptoms which do not appear to have an allergic aetiology are relatively prevalent (17.2%). Where sensitisation to ingredients arises, fungal amylase present in bread improvers is the principal allergen.