Yellow jacket venom (YJV) contains acid phosphatase, hyaluronidase and phospholipase but neither allergen C nor melittin as in bee venom (BV). YJV enzymes did not cross react with antisera to BV enzymes. YJV was separated into 7 fractions, all of which had some activity in RAST [radioallergosorbent tests]. Sera were specific for the fractions containing phospholipase and acid phosphatase. The other 3 protein fractions exhibited substantial RAST activity, suggesting there are at least 5 allergens in YJV.