Occupational allergy due to hypersensitivity to cereal flours is relatively common among bakers and grain-store workers. Storage mites can contaminate wheat flour and could be an important cause of allergic symptoms due to inhalation. Forty-three patients with criteria for allergic sensitization to wheat flour (skin tests, specific IgE to wheat flour and positive challenge tests) were included in a study to investigate the prevalence of cosensitization to Lepidoglyphus destructor (Ld). This mite was the predominant species in the wheat flour samples supplied by our patients. We found that 30% of the patients had IgE-mediated hypersensitivity of Ld. Of these, 23% did not have a relationship with any bakery or agriculture. We conclude that the prevalence of sensitization to Ld in patients sensitized to wheat flour is important.