Background: Effective teamwork and communication are key elements of patient safety. This is especially true in the pediatric emergency department where patient volume, acuity and the intermingling of a large inter-professional staff may make clear, effective and timely communication challenging. Ineffective communication has been associated with medical errors and poor outcomes. Closed loop communication (CLC) promotes clarity and a shared mental model by allowing team members to verbalize (call out), confirm (acknowledge and checkback) and close the loop about their understanding of information. Purpose: Our objective was to create a simulation based training curriculum that would promote closed loop communication amongst the multidisciplinary members of a pediatric emergency department. We hypothesized that the simulation sessions would improve our staff’s perceptions of their ability to close the loop in communication. Methods: Staff members watched three videos of simulated resuscitation scenarios; one with team members using poor CLC, another using good CLC, and the third with the team leader blindfolded with seamless CLC. This was followed by a facilitated discussion about the value of CLC. Each staff member then participated in 2 different simulations. The first was 15 minutes in length, involved at most 4 team members and focused on targeted individualized training about proper CLC techniques. The second was an hour long medical resuscitation that utilized a 6 member team and required an integrated use of CLC throughout the resuscitation. A debrief followed that focused on integrating CLC in high stakes, low frequency events as well as daily tasks. Using a 1-10 likert scale, staff rated their perceptions about their own and their team’s CLC ability prior to (pre) and immediately after the 15 minute simulation (post 1) and immediately after the hour long simulation (post 2). Results: 70 simulations were conducted over the span of 13 weeks, forty 15 minute and 30 hour long simulations. Participants included ED attendings, fellows, nurses, techs and PAs. Data may be found in Tables 1 and 2. Conclusions: Simulation is an effective tool to train staff how to properly close the loop in communication. Ongoing training is needed to ensure that the skills are sustained. Future studies are needed to better delineate the frequency with which this training must occur.