The wide-spread use of soybean [Glycine max (L.) Merr.] products in processed foods poses a potential threat to soybean-sensitive, food-allergic individuals. Clinical symptoms of soybean allergy can be manifested as gastric distress or atopic dermatitis and, while usually not life threatening, suspected cases of anaphylaxis have been reported. In vitro assays of soybean seed proteins with sera collected from soybean-sensitive individuals have shown that major storage proteins as well as other minor seed proteins account for IgE binding. Gly m Bd 30k, a member of the papain superfamily of cysteine proteases, also referred to as P34, has been identified as a major allergen in soybean seeds. We have used gene silencing to eliminate accumulation of P34/Gly m Bd 30k in transgenic soybean. These transgenic plants, producing P34/Gly m Bd 30k-null seeds, lacked any obvious developmental or phenotypic differences when compared with control plants. The production of a P34/Gly m Bd 30k-null line eliminates one of the primary allergens present in soybean seeds.