A case of anaphylaxis is reported after IUI with sperm processed in Tyrode's solution supplemented with BSA. The patient had a positive prick cutaneous test to BSA and also had specific IgE antibody against it. Repeat IUI using the patient's own blood serum instead of BSA for processing the sperm proceeded without incident. Clinicians should be aware of this rare, but not inconsequential, adverse effect of using xenogeneic proteins during IUI and other assisted reproductive techniques.