Teamwork failures have been directly linked with medical errors and adverse patient events. As a result, multiple efforts have been made to improve the leadership and performance of healthcare teams. Two studies will be presented that assess team training effects on teamwork behaviors and patient outcomes for emergency medical teams. In the first study, a computer-based team training program was designed to familiarize emergency medical residents on eight teamwork processes. Results showed teams that received this training were significantly better than placebo training teams on both teamwork and patient care outcomes in high-fidelity simulated patient resuscitation scenarios. In the second study, a simulated-based team leadership training program was designed to train trauma team leaders on behaviors important to action team leadership. In a randomized controlled trial, trauma team leaders were video recorded in actual trauma resuscitations, before and after training. Results showed a significant difference in post-training leadership behaviors between the training and control conditions. Furthermore, leadership behaviors were found to mediate an effect of training on patient care with a significant indirect effect.