Objectives: Extracorporeal membrane oxygenation–related complications are potentially catastrophic if not addressed quickly. Because complications are rare, high-fidelity simulation is recommended as part of the training regimen for extracorporeal membrane oxygenation specialists. We hypothesized that the use of standardized checklists would improve team performance during simulated extracorporeal membrane oxygenation emergencies. Design: Randomized simulation-based trial. Setting: A quaternary-care academic hospital with a regional extracorporeal membrane oxygenation referral program. Subjects: Extracorporeal membrane oxygenation specialists and other healthcare providers. Interventions: We designed six read-do checklists for use during extracorporeal membrane oxygenation emergencies using a modified Delphi process. Teams of two to three providers were randomized to receive the checklists or not. All teams then completed four simulated extracorporeal membrane oxygenation emergencies. Measurements and Main Results: Simulation sessions were video-recorded, and the number of critical tasks performed and time-to-completion were compared between groups. A survey instrument was administered before and after simulations to assess participants’ attitudes toward the simulations and checklists. We recruited 36 subjects from a single institution, randomly assigned to 15 groups. The groups with checklists completed more critical tasks than participants in the control groups (90% vs 75%; p < 0.001). The groups with checklists performed a higher proportion of both nontechnical tasks (71% vs 44%; p < 0.001) and extracorporeal membrane oxygenation–specific technical tasks (94% vs 86%; p < 0.001). Both groups reported an increase in reported self-efficacy after the simulations (p = 0.003). After adjusting for multiple comparisons, none of the time-to-completion measures achieved statistical significance. Conclusions: The use of checklists resulted in better team performance during simulated extracorporeal membrane oxygenation emergencies. As extracorporeal membrane oxygenation use continues to expand, checklists may be an attractive low-cost intervention for centers looking to reduce errors and improve response to crisis situations.