Use of the World Health Organization's Surgical Safety Checklist has been associated with a significant reduction in major postoperative complications after inpatient surgery. We hypothesized that implementing the checklist in the United States would generate cost savings for hospitals. We performed a decision analysis comparing implementation of the checklist to existing practice in U.S. hospitals. In a hospital with a baseline major complication rate after surgery of at least 3 percent, the checklist generates cost savings once it prevents at least five major complications. Using the checklist would both save money and improve the quality of care in hospitals throughout the United States.