Prick tests were performed with "pneumallergerns" (mites, cereal dusts, animal dander, pollens, moulds--totalling 35 allergens) among 742 agricultural workers of the Meuse department (North East of France) as part of an epidemiological study on respiratory and immuno-allergological problems. Among those with positive skin tests, 47.9% had positive skin tests for mites, 22.4% for cereal dusts, 10.7% for animals, 12.7% for pollens and 7.8% for moulds. Polysensitization was frequent (19.5% of the population). When the skin test was positive for main house dust mites it frequently was positive for storage mites, too. Among vegetal dusts sensitization, soy bean allergy yielded the highest frequency (6.5%). As for animal sensitization, cow dander was the most frequently observed positive test. Sensitization to pollens and moulds was comparatively rare. This study shows the large frequency and diversity of "latent allergy" to pneumallergens among agricultural workers.