SKin testing was done on 30 patients with a history of anaphylactic reactions after a Hymenoptera sting and on 30 control subjects. The patients all had positive basophilhistamine release to one or more venoms on challenge with the specific venoms used for skin testing (honey bee, yellow jacket, white-faced hornet, yellow hornet, and Polistes). At 0.1 mug of venom/ml and at 1.0 mug of venom/ml, 75% and 100%, respectively, of the sensitive patients had a positive skin test. There was a significant (P less than 0.001) correlation between skin test and histamine release results. Of the 150 skin tests in control patients, only 1 was positive. Venom skin tests provide, for the first time, a simple, readily available technique to accurately diagnose allergy to stinging insects.