We report on four patients sensitized to sunflower seed. Three of them developed anaphylaxis and one chronic bronchial asthma. All four patients reacted the first time sunflower seeds were ingested, and all had kept cage birds fed on sunflower seeds. Therefore, the route of sensitization was probably by inhalation of airborne sunflower seed allergens. Investigation of this type of hypersensitivity in 84 atopic patients showed that only three patients were RAST-positive, indicating that this allergy is fairly uncommon. On the other hand, when atopic persons are exposed to cage birds, the rate of sensitization is rather high, as indicated by the fact that in this category 79% were skin prick positive and 21% were unequivocably RAST positive to sunflower seed.