Hypersensitivity reactions to reindeer epithelial (RE) allergens have been recently demonstrated among reindeer herders. To determine the concentration of airborne RE antigens a method based on inhibition of the enzyme-linked immunosorbent assay (ELISA) was developed. Dust samples were collected in workshops where reindeer leather was processed and the workers had inhaled dry epithelial dust during their working shifts. Specific IgE to RE allergen could be detected in one of 5 workers. RE antigen concentrations varied from 0.01 microgram to 3.9 micrograms/m3 in the air of the workshop. All workers except one claimed work-associated respiratory symptoms.