Introduction: Simulation is becoming widely adopted across medical disciplines and by different medical professionals. For medical students, emergency medicine simulation has been shown to increase knowledge, confidence and satisfaction. At the University of Ottawa Skills and Simulation Centre, third-year medical students participate in simulated scenarios common to Emergency Medicine (EM) as part of their mandatory EM clerkship rotation. This study aims to evaluate simulation as part of the EM clerkship rotation by assessing changes in student confidence following a simulation session. Methods: In groups of seven, third year medical students at the University of Ottawa completed simulation sessions of the following: Status Asthmaticus, Status Epilepticus, Urosepsis and Breaking Bad News. Student confidence with each topic was assessed before and after simulation with a written survey. Confidence scores pre- and post-simulation were compared with the Wilcoxon signed rank test. Results: Forty-eight third years medical students in their core EM clerkship rotation, between September 2017 and August 2018 participated in this study. Medical student confidence with diagnosis of status asthmaticus (N = 44, p = 0.0449) and status epilepticus (N = 45, p = 0.0011) increased significantly following simulation, whereas confidence with diagnosis of urosepsis was unchanged (N = 45, p = 0.0871). Treatment confidence increased significantly for status asthmaticus (N = 47, p = 0.0009), status epilepticus (N = 48, p = 0.0005) and urosepsis (N = 48, p < 0.0001). Confidence for breaking bad news was not significantly changed after simulation (N = 47, p = 0.0689). Conclusion: Simulation training in our EM clerkship rotation significantly increased the confidence of medical students for certain common EM presentations, but not for all. Further work will aim to understand why some simulation scenarios did not improve confidence, and look to improve existing scenarios.