<h3>Objective:</h3> To assess the impact of an acute ischemic stroke (AIS) simulation course on residents’ performance, confidence, and knowledge. <h3>Background:</h3> Previous studies have demonstrated that simulation can promote mastery learning in non-stroke neurological emergencies. <h3>Design/Methods:</h3> We designed an AIS simulation course with three independent scenarios based on previously reported consensus. For each scenario a Minimum Passing Score (MPS) and Mastery Score (MS) was determined by the Angoff method. Thirteen junior neurology residents completed a 20-point knowledge test and 7-point Likert scale confidence survey about AIS before the course and after didactic teaching. A week later, each resident participated in a scored AIS case and then practiced stroke care in second unscored case. Residents again completed the knowledge and confidence assessments. Several weeks later, without notice, each resident was evaluated in a third AIS scenario. For comparison, eight senior residents completed the knowledge test, confidence survey, and the third acute stroke case. Pre-post and between groups comparisons were conducted using paired t-tests and independent t-tests, respectively. <h3>Results:</h3> Junior residents scored better on the knowledge test after the didactic session (mean score pre: 40% to post: 52.2%, p<0.05), but only 3 (23%) initially achieved the MPS score in the first AIS simulation. After the simulation course, 9 junior residents (69%) achieved the MPS threshold. Although none achieved Mastery, junior residents’ mean score in the simulation improved (10.3 (SD=2.8) vs 15.7 (SD=2.6), p<0.001) and their confidence increased (pre mean=3.3 (SD=1.9) vs. post mean =4.9 (SD=1.2), p< 0.001). Eight seniors completed the simulation: five reached MPS (63%) and one achieved Mastery. The simulation scores of the post-course juniors and seniors were similar (mean=15.7 (SD=2.6) vs mean=16.0 (SD=2.5), p=0.793). <h3>Conclusions:</h3> This pilot study suggests that a brief AIS simulation course may improves junior residents’ performance and confidence to a level similar to senior residents, but not to mastery. <b>Disclosure:</b> Dr. Albin has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Continuum: Life Long Learning in Neurology. Dr. Albin has received research support from American Academy of Neurology. Dr. Albin has received publishing royalties from a publication relating to health care. Dr. Albin has received personal compensation in the range of $500-$4,999 for serving as a Instructor with Resuscitation Leadership Academy. Dr. Sigman has nothing to disclose. Dr. Pergakis has nothing to disclose. Dr. Bhatt has nothing to disclose. Dr. Hutto has nothing to disclose. Dr. Koneru has nothing to disclose. Dr. Osehobo has nothing to disclose. Dr. Vizcarra has nothing to disclose. The institution of Dr. Morris has received research support from American Board of Psychiatry and Neurology. The institution of Dr. Morris has received research support from UMB ICTR through NIH NCATS&CTSA grant 1UL1TR003098. The institution of Dr. Morris has received research support from University of Maryland Medical Center.