Teamwork training programs have resulted in some notable successes, but many other attempts have failed to yield improved patient outcomes, in part because of a lack of evidence showing that teamwork training results in durable provider behavior change. In this AHRQ-funded study, the TeamSTEPPS training program was introduced in two intensive care units (one pediatric and one adult surgical), after meticulous preparatory planning that emphasized the utility of the training for frontline care providers, engaged higher-level support for the effort, and established clear metrics for effectiveness. The program resulted in improvement in directly observed team behaviors and measures of safety culture, and also improved 2 of 3 targeted patient-level outcomes. A related editorial discusses the role of targeted teamwork training interventions in the context of efforts to develop high reliability organizations.