BACKGROUND: Many bundles have proven effective at preventing surgical site infections (SSIs), but little is known about factors influencing compliance to such bundles. METHODS: This cohort study includes 41,400 surgeries performed in 47 hospitals throughout a decade. The outcome of interest was binary compliance with a 4-element bundle for SSI prevention. A multivariable logistic regression model was computed with 12 predictor variables: patient sex, age, American Society of Anesthesiologists score, surgical specialty, length of preoperative stay, procedure year, procedure duration, surgical technique, presence of a prosthetic implant, elective versus emergent procedure, hospital type, and hospital size. RESULTS: Bundle compliance has increased significantly since its implementation, reaching 67.1% in the latest year. Lower odds of bundle compliance are correlated with emergent procedures (OR 0.3697), procedure duration above the first tertile (0.8597), age above the first quartile (0.7365), absence of a prosthetic implant, open surgical technique, and preoperative stay above 1 day (0.7920). DISCUSSION: Older age, longer procedure duration, longer preoperative stay, and an open surgical technique all correlate negatively with bundle compliance and are also known risk factors for SSIs. CONCLUSIONS: Certain patient subgroups are at higher risk for bundle noncompliance, and thus show greater margins for improvement.