Background Suicide is a leading yet underestimated cause of death in the world and in France. The goal of our study was to determine the impact at 3 months of a large-scale simulation program on suicide risk assessment for first-year medical residents. Methods All the first-year medical residents participated in the simulation program that included a session on suicide risk assessment. The scenario was carried out by a standardized patient (professional actor) who had a normal check-up at the ER after a chest pain. He verbalized suicidal thoughts to an ER nurse due to a recent divorce and social difficulties, who then reported it to the resident. The latter had to assess suicide risk on his own. The QECS “Questionnaire de connaissances relatives au suicide” was used to assess knowledge of suicide before the training session (T0) and 3 months later (T1). A pre/post comparison was performed with a paired t-test. Results 420 residents participated in this study. A total of 273 matching questionnaires was obtained. A statistically significant theoretical knowledge improvement was found at 3 months of the session for all the residents. Limitations The absence of a control group and data loss were some of the major limitations of our study. Another limitation corresponds to the lack of additional questions, such as levels of interest, former and recent training, level of experience, attitudes, and self-competency in suicide risk assessment before and after the simulation program that could have helped to interpret the obtained results and their variation. Moreover, the exact effects of this increased knowledge on clinical practice has not been measured in our study. Conclusion This is an unprecedented, large-scale attempt in France to allow all the medical residents to practice suicide risk assessment. This simulation-based training had a positive impact at 3 months on the knowledge of suicide in medical residents.