We report a case of a 17-year-old female adolescent who experienced an episode of exercise-induced anaphylactic reaction following ingestion of tuna sandwich (from soy containing canned tuna). Her medical history revealed that she had previously had one episode of urticaria after ingestion of sulfamethoxazole with trimethoprim and anaphylactic reaction after ingestion of sunflower nuts. Skin prick tests and specific immunoglobulin E antibody to tuna were negative, and to soy were positive. Treadmill exercise induced test in fasting state and 1 hour after a fresh tuna meal and meal not containing soy were negative. However, an exercise challenge test one hour after soy ingestion resulted in pruritus of hands, shoulders and back, urticarial lesions of the face and neck with angioedema of the lips and eyelids, hoarseness, tachycardia and anxiety.