Background. Despite the high prevalence of patient-reported antibiotic allergy (so-called antibiotic allergy labels AALs) and their impact on antibiotic prescribing, incorporation of antibiotic allergy testing (AAT) into antimicrobial stewardship (AMS) programs (AAT-AMS) is not widespread. We aimed to evaluate the impact of an AAT-AMS program on AAL prevalence, antibiotic usage, and appropriateness of prescribing. Methods. AAT-AMS was implemented at two large Australian hospitals during a 14-month period beginning May 2015. Baseline demographics, AAL history, age-adjusted Charlson comorbidity index, infection history, and antibiotic usage for 12 months prior to testing (pre–AAT-AMS) and 3 months following testing (post–AAT-AMS) were recorded for each participant. Study outcomes included the proportion of patients who were "de-labeled" of their AAL, spectrum of antibiotic courses pre– and post–AAT-AMS, and antibiotic appropriateness (using standard definitions). Results. From the 118 antibiotic allergy—tested patients, 226 AALs were reported (mean, 1.91/patient), with 53.6% involving 1 or more penicillin class drug. AAT-AMS allowed AAL de-labeling in 98 (83%) patients–56% (55/98) with all AALs removed. Post– AAT, prescribing of narrow-spectrum penicillins was more likely (adjusted odds ratio aOR, 2.81, 95% confidence interval CI, 1.45–5.42), as was narrow-spectrum β-lactams (aOR, 3.54; 95% CI, 1.98–6.33), and appropriate antibiotics (aOR, 12.27; 95% CI, 5.00–30.09); and less likely for restricted antibiotics (aOR, 0.16; 95% CI, 09–.29), after adjusting for indication, Charlson comorbidity index, and care setting. Conclusions. An integrated AAT-AMS program was effective in both de-labeling of AALs and promotion of improved antibiotic usage and appropriateness, supporting the routine incorporation of AAT into AMS programs.