© 2020 American Medical Association. All rights reserved. Importance: Surgical site infections (SSIs) are associated with increased morbidity and mortality. Various measures have been enacted decrease the occurrence of SSIs involving the regulation of the attire worn by the operating room staff, at times without sufficient peer-reviewed literature to support their implementation. Objective: To evaluate whether the combination of mandated surgical jackets and bouffants in the operating room is associated with the risk of surgical site infection. Design, Setting, and Participants: A retrospective cohort study of 34042 inpatient surgical encounters at a large academic tertiary care hospital was performed. Three periods between January 2017 and October 2018 were compared, corresponding with implementation of surgical jackets and the subsequent mandate of surgical jackets plus bouffant head covers. All inpatient surgical cases were included from University of Alabama at Birmingham University Hospital, a single-center, large academic tertiary care hospital. The study comprised a consecutive sample of all inpatient surgical cases over a 22-month period. Exposures: No surgical jackets or bouffants mandated (8 months), surgical jackets mandated (6 months), both surgical jackets and bouffants mandated (8 months). Main Outcomes and Measures: The primary study outcome was SSIs, which were collected from institutional infection control monthly summary reports, according to the National Healthcare Safety Network definitions for superficial incisional, deep incisional, and organ/space SSIs. Secondary outcomes included wound dehiscence, postoperative sepsis, death, and cost of interventions. Results: A total of 34042 inpatient surgical encounters cases were included in the analysis over the 22-month study period. Of the total patients, 16380 were women (48%) and 17638 were men (52%). There was no significant difference in the risk of SSI (1.01% vs 0.99% vs 0.83%; P =.28), mortality (1.83% vs 2.05% vs 1.92%; P =.54), postoperative sepsis (6.60% vs 6.24% vs 6.54%; P =.54), or wound dehiscence (1.07% vs 0.84% vs 1.06%; P =.20) between the 3 groups. Receipts from the first 6 months of the 2018/2019 fiscal year provided an estimated expenditure of more than $300000 annually on surgical jackets. Bouffants were found to be less expensive than surgical skull caps. Conclusions and Relevance: The results of this study suggest that surgical jackets and bouffants are neither beneficial nor cost-effective in preventing SSIs. Institutions should evaluate their own data to determine whether recommendations by outside governing organizations are beneficial and cost-effective.