AbstractBackground:Surgical-site infections (SSIs) can be catastrophic. Bundles of evidence-based practices can reduce SSIs but can be difficult to implement and sustain.Objective:We sought to understand the implementation of SSI prevention bundles in 6 US hospitals.Design:Qualitative study.Methods:We conducted in-depth semistructured interviews with personnel involved in bundle implementation and conducted a thematic analysis of the transcripts.Setting:The study was conducted in 6 US hospitals: 2 academic tertiary-care hospitals, 3 academic-affiliated community hospitals, 1 unaffiliated community hospital.Participants:In total, 30 hospital personnel participated. Participants included surgeons, laboratory directors, clinical personnel, and infection preventionists.Results:Bundle complexity impeded implementation. Other barriers varied across services, even within the same hospital. Multiple strategies were needed, and successful strategies in one service did not always apply in other areas. However, early and sustained interprofessional collaboration facilitated implementation.Conclusions:The evidence-based SSI bundle is complicated and can be difficult to implement. One implementation process probably will not work for all settings. Multiple strategies were needed to overcome contextual and implementation barriers that varied by setting and implementation climate. Appropriate adaptations for specific settings and populations may improve bundle adoption, fidelity, acceptability, and sustainability.