Background: Surgical site infections are reduced by appropriate and timely antimicrobial prophylaxis. Consensus guidelines recommend that antimicrobial infusion begin within 60 min prior to creation of the incision. An internal audit of our institution suggested poor guideline compliance. We hypothesized that the addition of a oral antibiotic verification to the routine preoperative patient identification, operation, and surgical site verification would increase compliance. To this end, we compared compliance with the guidelines before and after the addition of a verification of antibiotic administration to the routine preoperative protocol. Methods: We performed a retrospective medical record review of operations during two five-day periods, one prior to and one after the addition of the antibiotic verification. We identified operative procedure, time of antibiotic administration, time of incision, and the patient's preoperative inpatient or outpatient status. We excluded from analysis patients whose procedure did not require antibiotic prophylaxis, inpatients, and patients without complete records. Administration of antimicrobial prophylaxis was considered timely (≤60 min prior to incision), early (>60 min prior to incision), late (beginning after incision), or not given (no antibiotic administered). Comparisons were made using the χ2 statistic for noncontinuous variables with significance defined as p ≤ 0.05. Results: A total of 715 cases were reviewed. Excluded were 315 cases that did not require antibiotic prophylaxis, 88 inpatient procedures, and 22 cases with incomplete records. In the pre-intervention group, 87 of 97 cases (90%) demonstrated timely antibiotic administration. In the post-intervention group, 163 of 193 cases (85%) received timely antibiotic prophylaxis. Although pre-intervention compliance was slightly better than post-intervention, this difference was not significant (p = 0.223). Conclusion: The addition of verification of timely antimicrobial prophylaxis to the routine preoperative verifications does not improve compliance with the prophylaxis guidelines in the setting of good pre-intervention compliance.