The World Health Organization's Safe Surgery Saves Lives program generated noteworthy attention when implementation of a 19-item checklist reduced morbidity and mortality in a global population. This study builds on those findings by examining the role of safety culture among participating teams, and its potential effect in contributing to the remarkable clinical outcomes. Using the safety attitudes questionnaire, investigators found a small but significant increase in mean teamwork and safety climate scores among operating room personnel. These changes did correlate with the degree of improvement in postoperative morbidity and mortality. Interestingly, nearly all respondents reported wanting the checklist themselves if they were undergoing an operation, which suggests the importance of face validity in the intervention. The authors conclude that some portion of their checklist intervention's success may be mediated by these changes in safety attitudes. This finding supports increasing literature demonstrating the importance of safety culture in producing desired clinical outcomes. A past AHRQ WebM&M perspective and interview discussed establishing a safety culture.