A penicillin allergy skin-testing service run by pharmacists is described. A board-certified allergist trained pharmacists at a tertiary care teaching hospital to administer penicillin allergy skin tests and interpret the results. A major objective of the service was to avoid unnecessary use of vancomycin and quinolones in patients claiming but not actually having a penicillin allergy. Patients with a severe type I reaction to penicillin during the preceding five years, patients with a confirmed history of a type II-IV reaction to penicillin, and severely immunosuppressed patients were not eligible for testing. As of July 2003, 26 patients had been enrolled in the service. A type I penicillin reaction was ruled out by the drug allergy history for 3 patients. The results were negative in 22 of the 23 patients who received skin testing, and in 1 the result was indeterminate. A penicillin or a beta-lactam antibiotic was administered to all 26 patients. No patient had a significant adverse reaction to skin testing or drug administration. A pharmacist-managed penicillin allergy skin-testing service was well received by physicians and showed potential to avoid unnecessary use of alternative antibiotics.