Two published studies from the 1970s describe a higher inappropriate use of antimicrobials among surgeons compared to internal medicine physicians. If this assertation is indeed true, institutions with limited resources should focus interventions on surgical services to improve antimicrobial use. The appropriateness of antimicrobial use in internal medicine and general surgical patients over a 10-month period was evaluated at the University of Louisville Hospital (Louisville, Ky) based upon established institutional antimicrobial guidelines. Antimicrobial selection and dose were evaluated for 1,300 antimicrobial courses. Compliance to institutional guidelines for antimicrobial selection and dose were found in 448 (93%) of 480 courses prescribed by internal medicine services and 728 (88%) of 820 courses prescribed by surgical services (P=.009). Although we were able to identify a 5% difference among specialties, we did not consider this to be a clinically significant difference. We concluded that focused interventions to improve antimicrobial use at the University of Louisville should be applied equally to medical and surgical specialties.